[SCSI] qla2xxx: changes in multiq code

Following changes have been made:
 1. Scan outstanding commands only in the queue where it is submitted
 2. Update queue registers directly in the fast path
 3. Queue specific BAR is remapped only for multiq capable adapters

Signed-off-by: Anirban Chakraborty <anirban.chakraborty@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>