ASoC: simple-card: keep the property's name the same pattern

Even though we might not have rigor rule for the simple card property names,
according to the existing ones, they are all in a same pattern:

[simple-audio-card,]XXX;

Rename simple-audio-routing to simple-audio-card,routing, and make the simple
card's properties has one unified name.

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Mark Brown <broonie@linaro.org>