scsi: ufs: core: Improve static type checking

Introduce an enumeration type for the overall command status to allow the
compiler to perform more static type checking.

Link: https://lore.kernel.org/r/20211020214024.2007615-4-bvanassche@acm.org


Acked-by: Avri Altman <Avri.Altman@wdc.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>