scsi: qla2xxx: Add fw_started flags to qpair

Add fw_started flag to qpair to reduce cache thrash.  This reduce access
to qla_hw_data structure by each qpair.

Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>