[SCSI] aacraid: Add likely() and unlikely()

Add some likely() and unlikely() compiler hints in some of the aacraid
hardware interface layers. There should be no operational side effects
resulting from this patch and the changes should be mostly benign on x86
platforms.

Signed-off-by: Mark Salyzyn <aacraid@adaptec.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>