[ALSA] soc - tlv320aic3x - add GPIO support

This patch adds support for AIC3x GPIO lines. They can be configured for
many possible functions as well as be driven manually. I also introduced
i2c read functionality since the GPIO state register has to be read from
hardware every time and can not be served from cache.

Signed-off-by: Daniel Mack <daniel@caiaq.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>