aacraid: Add Power Management support

* .suspend() and .resume() routines implemented in the driver
* aac_release_resources() initiates firmware shutdown
* aac_acquire_resources re-initializes the host interface

Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Reviewed-by: Murthy Bhat <Murthy.Bhat@pmcs.com>
Reviewed-by: Karthikeya Sunkesula <Karthikeya.Sunkesula@pmcs.com>
Signed-off-by: Mahesh Rajashekhara <Mahesh.Rajashekhara@pmcs.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>