ALSA: ASoC: pxa: add asoc pm callbacks to pxa audio drivers

After convertion to snd_soc_register_card, platform driver should
reference snd_soc_pm_ops callbacks to properly suspend/resume sound
hardware. This was missed during conversion of PXA sound devices.

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: Mark Brown <broonie@linaro.org>