[media] Add support for AUX_PLL on cx2583x chips

This adds support for the AUX_PLL in cx2583x chips which is available in
those although the audio part of the chip is not.
The AUX_PLL is used at least by Terratec in their Grabster AV400 device.

Signed-off-by: Sven Barth <pascaldragon@googlemail.com>
Acked-by: Mike Isely <isely@pobox.com>
Reviewed-by: Andy Walls <awalls@md.metrocast.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>