[SCSI] aacraid: fix shutdown handler to also disable interrupts.

Moves quiesce, thread and interrupt shutdown into aacraid drivers'
.shutdown handler. This fix to the aac_shutdown handler will remove the
superfluous reset of the adapter during a (clean) kexec.

This fix may mitigate the active investigation 'kexec and aacraid
broken' but it is unlikely to affect the root cause (issue likely
present in both kexec and kdump). This patch reduces the chance the
problem will occur with a kexec. The fix for root cause is currently
expected to be the minimum value check to the aacraid.startup_timeout
driver variable after an adapter reset within aacraid_commit_reset.patch
submitted on 05/22/2007 and awaiting testing by Yinghai to confirm.

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