[SCSI] bfa: Update RME interrupt handling.

- Made changes to always acknowledge RME interrupt and update
  consumer index (CI) when RME interrupt is generated.
- Made changes to have ASIC specific hw_rspq_ack() handler.

Signed-off-by: Krishna Gudipati <kgudipat@brocade.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>