ASoC: WM8804: Initial driver

The WM8804 is a high performance consumer mode S/PDIF transceiver with
support for 1 received channel and 1 transmitted channel.

Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>