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

In file included from  drivers/scsi/ipr.c:73:
 drivers/scsi/ipr.c: In function ‘ipr_mask_and_clear_interrupts’:
 drivers/scsi/ipr.c:740:15: warning: variable ‘int_reg’ set but not used [-Wunused-but-set-variable]
 drivers/scsi/ipr.c: In function ‘ipr_cancel_op’:
 drivers/scsi/ipr.c:5497:13: warning: variable ‘int_reg’ set but not used [-Wunused-but-set-variable]
 drivers/scsi/ipr.c: In function ‘ipr_iopoll’:
 drivers/scsi/ipr.c:5765:22: warning: variable ‘ioa_cfg’ set but not used [-Wunused-but-set-variable]
 drivers/scsi/ipr.c: In function ‘ipr_reset_restore_cfg_space’:
 drivers/scsi/ipr.c:8662:6: warning: variable ‘int_reg’ set but not used [-Wunused-but-set-variable]
 drivers/scsi/ipr.c: In function ‘ipr_test_msi’:

Link: https://lore.kernel.org/r/20200713080001.128044-14-lee.jones@linaro.org
Cc: Brian King <brking@us.ibm.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>