[SCSI] aacraid: remove unneeded locking

Received From Mark Salyzyn

Since new commands to the card are quiesced, respect the changes in
the SCSI error path which dropped locking around the hba reset handler
and similarly drop the lock requirement in the driver's path.

Signed-off-by: Mark Haverkamp <markh@osdl.org>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>