ALSA: Separate common pxa2xx-ac97 code

ASoC and non-ASoC drivers for ACLINK on PXA share lot's of common code.
Move all common code into separate module snd-pxa2xx-lib.

[Fixed handing of SND_AC97_CODEC in Kconfig and some checkpatch warnings
 -- broonie]

Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>