scsi: qla2xxx: Move marker request behind QPair

Current code hard codes marker request to use request and response queue
0. This patch make use of the qpair as the path to access the
request/response queues.  It allows marker to be place on any hardware
queue.

Signed-off-by: Quinn Tran <qtran@marvell.com>
Signed-off-by: Himanshu Madhani <hmadhani@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>