[ALSA] ASoC pxa2xx I2S support

This patch adds pxa2xx I2S ASoC audio support. Features:-
 o Supports playback/capture
 o 16 bit PCM
 o 8k - 96k sample rates
 o Supports master and slave mode.
From: Liam Girdwood <liam.girdwood@wolfsonmicro.com>
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Liam Girdwood <liam.girdwood@wolfsonmicro.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>