scsi: qla2xxx: move fields from qla_hw_data to qla_qpair

- Move chip_reset, enable_class_2 fields from qla_hw_data to qla_qpair
  to reduce cache thrash for target MQ.
- Optimizations to reduce unnecessary memory load for good path io.

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>