[SCSI] aacraid: Added Sync.mode to support series 7/8/9 controllers

Added Sync. mode to support Series 7/8/9 controller families: This is a
compatibility mode for all these controller families. The Async. (Performance)
mode can be changed in the future.  First Async. mode version added for Series
7; Controller parameter aac_sync_mode added

Signed-off-by: Mahesh Rajashekhara <aacraid@pmc-sierra.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>