[SCSI] fnic: potential dead lock in fnic_is_abts_pending()

There is an unlock missing if the == FNIC_IOREQ_ABTS_PENDING is
false.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Hiral Patel <hiralpat@cisco.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>