scsi: ufs: Document all return values

This patch fixes multiple W=2 kernel-doc warnings.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20230727194457.3152309-3-bvanassche@acm.org


Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>