ASoC: sdw-mockup: Switch to new snd_sdw_params_to_config helper

The conversion from hw_params to SoundWire config is pretty
standard as such most of the conversion can be handled by the new
snd_sdw_params_to_config helper function.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20221123165432.594972-9-ckeepax@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>