scsi: pm80xx: Replace open coded check with dev_is_expander()

This is a follow up cleanup to the commit 924a3541 ("scsi: libsas:
aic94xx: hisi_sas: mvsas: pm8001: Use dev_is_expander()")

Link: https://lore.kernel.org/r/20210929025807.646589-1-ipylypiv@google.com


Reviewed-by: Vishakha Channapattan <vishakhavc@google.com>
Acked-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Igor Pylypiv <ipylypiv@google.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>