orion/kirkwood: add audio functions.

This patch add audio related definitions and functions

Signed-off-by: Arnaud Patard <apatard@mandriva.com>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>