Fix the following Wstringop-overflow warnings when building with GCC-11:

drivers/scsi/fcoe/fcoe.c: In function ‘fcoe_netdev_config’:
drivers/scsi/fcoe/fcoe.c:744:32: warning: ‘fcoe_wwn_from_mac’ accessing 32 bytes in a region of size 6 [-Wstringop-overflow=]
  744 |                         wwnn = fcoe_wwn_from_mac(ctlr->ctl_src_addr, 1, 0);
      |                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/scsi/fcoe/fcoe.c:744:32: note: referencing argument 1 of type ‘unsigned char *’
In file included from drivers/scsi/fcoe/fcoe.c:36:
./include/scsi/libfcoe.h:252:5: note: in a call to function ‘fcoe_wwn_from_mac’
  252 | u64 fcoe_wwn_from_mac(unsigned char mac[MAX_ADDR_LEN], unsigned int, unsigned int);
      |     ^~~~~~~~~~~~~~~~~
drivers/scsi/fcoe/fcoe.c:747:32: warning: ‘fcoe_wwn_from_mac’ accessing 32 bytes in a region of size 6 [-Wstringop-overflow=]
  747 |                         wwpn = fcoe_wwn_from_mac(ctlr->ctl_src_addr,
      |                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  748 |                                                  2, 0);
      |                                                  ~~~~~
drivers/scsi/fcoe/fcoe.c:747:32: note: referencing argument 1 of type ‘unsigned char *’
In file included from drivers/scsi/fcoe/fcoe.c:36:
./include/scsi/libfcoe.h:252:5: note: in a call to function ‘fcoe_wwn_from_mac’
  252 | u64 fcoe_wwn_from_mac(unsigned char mac[MAX_ADDR_LEN], unsigned int, unsigned int);
      |     ^~~~~~~~~~~~~~~~~
  CC      drivers/scsi/bnx2fc/bnx2fc_io.o
In function ‘bnx2fc_net_config’,
    inlined from ‘bnx2fc_if_create’ at drivers/scsi/bnx2fc/bnx2fc_fcoe.c:1543:7:
drivers/scsi/bnx2fc/bnx2fc_fcoe.c:833:32: warning: ‘fcoe_wwn_from_mac’ accessing 32 bytes in a region of size 6 [-Wstringop-overflow=]
  833 |                         wwnn = fcoe_wwn_from_mac(ctlr->ctl_src_addr,
      |                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  834 |                                                  1, 0);
      |                                                  ~~~~~
drivers/scsi/bnx2fc/bnx2fc_fcoe.c: In function ‘bnx2fc_if_create’:
drivers/scsi/bnx2fc/bnx2fc_fcoe.c:833:32: note: referencing argument 1 of type ‘unsigned char *’
In file included from drivers/scsi/bnx2fc/bnx2fc.h:53,
                 from drivers/scsi/bnx2fc/bnx2fc_fcoe.c:17:
./include/scsi/libfcoe.h:252:5: note: in a call to function ‘fcoe_wwn_from_mac’
  252 | u64 fcoe_wwn_from_mac(unsigned char mac[MAX_ADDR_LEN], unsigned int, unsigned int);
      |     ^~~~~~~~~~~~~~~~~
In function ‘bnx2fc_net_config’,
    inlined from ‘bnx2fc_if_create’ at drivers/scsi/bnx2fc/bnx2fc_fcoe.c:1543:7:
drivers/scsi/bnx2fc/bnx2fc_fcoe.c:839:32: warning: ‘fcoe_wwn_from_mac’ accessing 32 bytes in a region of size 6 [-Wstringop-overflow=]
  839 |                         wwpn = fcoe_wwn_from_mac(ctlr->ctl_src_addr,
      |                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  840 |                                                  2, 0);
      |                                                  ~~~~~
drivers/scsi/bnx2fc/bnx2fc_fcoe.c: In function ‘bnx2fc_if_create’:
drivers/scsi/bnx2fc/bnx2fc_fcoe.c:839:32: note: referencing argument 1 of type ‘unsigned char *’
In file included from drivers/scsi/bnx2fc/bnx2fc.h:53,
                 from drivers/scsi/bnx2fc/bnx2fc_fcoe.c:17:
./include/scsi/libfcoe.h:252:5: note: in a call to function ‘fcoe_wwn_from_mac’
  252 | u64 fcoe_wwn_from_mac(unsigned char mac[MAX_ADDR_LEN], unsigned int, unsigned int);
      |     ^~~~~~~~~~~~~~~~~
drivers/scsi/qedf/qedf_main.c: In function ‘__qedf_probe’:
drivers/scsi/qedf/qedf_main.c:3520:30: warning: ‘fcoe_wwn_from_mac’ accessing 32 bytes in a region of size 6 [-Wstringop-overflow=]
 3520 |                 qedf->wwnn = fcoe_wwn_from_mac(qedf->mac, 1, 0);
      |                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/scsi/qedf/qedf_main.c:3520:30: note: referencing argument 1 of type ‘unsigned char *’
In file included from drivers/scsi/qedf/qedf.h:9,
                 from drivers/scsi/qedf/qedf_main.c:23:
./include/scsi/libfcoe.h:252:5: note: in a call to function ‘fcoe_wwn_from_mac’
  252 | u64 fcoe_wwn_from_mac(unsigned char mac[MAX_ADDR_LEN], unsigned int, unsigned int);
      |     ^~~~~~~~~~~~~~~~~
drivers/scsi/qedf/qedf_main.c:3521:30: warning: ‘fcoe_wwn_from_mac’ accessing 32 bytes in a region of size 6 [-Wstringop-overflow=]
 3521 |                 qedf->wwpn = fcoe_wwn_from_mac(qedf->mac, 2, 0);
      |                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/scsi/qedf/qedf_main.c:3521:30: note: referencing argument 1 of type ‘unsigned char *’
In file included from drivers/scsi/qedf/qedf.h:9,
                 from drivers/scsi/qedf/qedf_main.c:23:
./include/scsi/libfcoe.h:252:5: note: in a call to function ‘fcoe_wwn_from_mac’
  252 | u64 fcoe_wwn_from_mac(unsigned char mac[MAX_ADDR_LEN], unsigned int, unsigned int);
      |     ^~~~~~~~~~~~~~~~~

by changing the array size to the correct value of ETH_ALEN in the
argument declaration.

Also, fix a couple of checkpatch warnings:
WARNING: function definition argument 'unsigned int' should also have an identifier name

This helps with the ongoing efforts to globally enable
-Wstringop-overflow.

Link: https://github.com/KSPP/linux/issues/181
Fixes: 85b4aa49 ("[SCSI] fcoe: Fibre Channel over Ethernet")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>