scsi: mpi3mr: Return error if dma_alloc_coherent() fails

Return -ENOMEM instead of success if dma_alloc_coherent() fails.

Link: https://lore.kernel.org/r/YnOmMGHqCOtUCYQ1@kili
Fixes: 43ca1100

 ("scsi: mpi3mr: Add support for PEL commands")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>