ASoC: rt1308-sdw: add the default value of register 0xc320

The driver missed the default value of register 0xc320.
This patch adds that default value to avoid the error messages
when the driver went to suspend mode already.

BugLink: https://github.com/thesofproject/linux/issues/3651
Signed-off-by: Shuming Fan <shumingf@realtek.com>
Link: https://lore.kernel.org/r/20220520090205.25857-1-shumingf@realtek.com
Signed-off-by: Mark Brown <broonie@kernel.org>