scsi: qla2xxx: Fix crash in qla2xxx_eh_abort on bad ptr

After a Qlogic card breaks when initializing (test case), the system can
crash in qla2xxx_eh_abort if processing anything but a scsi command type
srb.

Fixes: 1535aa75 ("scsi: qla2xxx: fix invalid DMA access after command aborts in PCI device remove")
Signed-off-by: Bill Kuzeja <william.kuzeja@stratus.com>
Acked-By: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>