scsi: qla2xxx: Move session delete to driver work queue

scsi: qla2xxx: Move session delete to driver work queue

commit a01c77d2cbc45ba527e884e5c30363a1200a4130 upstream.

Move session delete from system work queue to driver's work queue for in
time processing.

Fixes: 726b85487067d ("qla2xxx: Add framework for async fabric discovery")
Cc: <stable@vger.kernel.org> # 4.10+
Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>