cciss: make sure we request the performant mode irq

Make sure we register the performant mode interrupt Another blunder.
Seemed to work because the call to put_controller_into_performant_mode was
never called.

Signed-off-by: Mike Miller <mike.miller@hp.com>
Cc: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>