ASoC: omap-mcpdm: Support for suspend resume

Implement ASoC's suspend and resume callbacks.
Since McPDM does not use pcm_trigger for start and stop of the stream due
to strict sequencing needs with the twl6040, the callbacks will stop and
restart the McPDM in case the board suspended during audio activity.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>