ASoC: mchp-pdmc: add support for suspend to RAM

ASoC: mchp-pdmc: add support for suspend to RAM

Add support for suspend to RAM by re-aranging the lines in switch..case
from mchp_pdmc_trigger() and saving/restoring the enabled interrupts. These
are necessary as AT91 devices has a special power saving mode (called
backup and self-refresh) where most of the SoC parts are powered off
and thus we need to reconfigure the PDMC on resume.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20221213112851.89212-4-claudiu.beznea@microchip.com
Signed-off-by: Mark Brown <broonie@kernel.org>