scsi: pm8001: clean up dead code when PM8001_USE_MSIX is defined

When macro PM8001_USE_MSIX is defined there are redundant dead code calls
to pm8001_chip_intx_interrupt_{enable|disable} and pm8001_cr32.

Clean this up for the defined PM8001_USE_MSIX and undefined
PM8001_USE_MSIX cases.

[mkp: squashed two patches]

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>