Intentionally keeping all register reads/writes.

Fixes the following W=1 kernel build warning(s):

 drivers/scsi/ips.c: In function ‘ips_init_copperhead’:
 drivers/scsi/ips.c:4700:10: warning: variable ‘ConfigByte’ set but not used [-Wunused-but-set-variable]
 4700 | uint8_t ConfigByte[IPS_MAX_CONFIG_BYTES];
 | ^~~~~~~~~~
 drivers/scsi/ips.c: In function ‘ips_init_copperhead_memio’:
 drivers/scsi/ips.c:4794:10: warning: variable ‘ConfigByte’ set but not used [-Wunused-but-set-variable]
 4794 | uint8_t ConfigByte[IPS_MAX_CONFIG_BYTES];
 | ^~~~~~~~~~
 drivers/scsi/ips.c: In function ‘ips_init_phase1’:
 drivers/scsi/ips.c:6839:10: warning: variable ‘func’ set but not used [-Wunused-but-set-variable]
 6839 | uint8_t func;
 | ^~~~
 drivers/scsi/ips.c:6838:10: warning: variable ‘bus’ set but not used [-Wunused-but-set-variable]
 6838 | uint8_t bus;
 | ^~~

Link: https://lore.kernel.org/r/20200723122446.1329773-13-lee.jones@linaro.org
Cc: Adaptec OEM Raid Solutions <aacraid@microsemi.com>
Cc: ipslinux@adaptec.com
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>