ASoC: kirkwood: Add audio support to openrd client platforms

This patch is adding support for openrd client platforms. It's using
the cs42l51 codec and has one mic and one speaker plugs.

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