ASoC: tegra: add tegra machine driver using wm9712 codec

This adds a very simple machine driver using the Wolfson wm9712 AC97
codec.

Signed-off-by: Lucas Stach <dev@lynxeye.de>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>