scsi: scsi_transport_fc: Declare wwn_to_u64() argument const

Since the wwn_to_u64() function does not change its input, make its
argument const.

Cc: James Smart <james.smart@broadcom.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Steffen Maier <maier@linux.vnet.ibm.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

include/scsi/scsi_transport_fc.h

@@ -756,7 +756,7 @@ fc_remote_port_chkready(struct fc_rport *rport)
 	return result;
 }
 
-static inline u64 wwn_to_u64(u8 *wwn)
+static inline u64 wwn_to_u64(const u8 *wwn)
 {
 	return get_unaligned_be64(wwn);
 }