aacraid: performance improvement changes

Signed-off-by: Mahesh Rajashekhara <Mahesh.Rajashekhara@pmcs.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Murthy Bhat <Murthy.Bhat@pmcs.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>