scsi: qla2xxx: Really fix qla2xxx_eh_abort()

I'm not sure how this happened but the patch that was intended to fix abort
handling was incomplete. This patch fixes that patch as follows:

 - If aborting the SCSI command failed, wait until the SCSI command
   completes.

 - Return SUCCESS instead of FAILED if an abort attempt races with SCSI
   command completion.

 - Since qla2xxx_eh_abort() increments the sp reference count by calling
   sp_get(), decrement the sp reference count before returning.

Cc: Himanshu Madhani <hmadhani@marvell.com>
Fixes: 219d27d7 ("scsi: qla2xxx: Fix race conditions in the code for aborting SCSI commands")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Himanshu Madhani <hmadhani@marvell.com>
Reviewed-by: Himanshu Madhani <hmadhani@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>