ASoC: SDCA: Add helper to write out defaults and fixed values

ASoC: SDCA: Add helper to write out defaults and fixed values

The concept of an SDCA default value differs slightly from the regmap
usage of the term. An SDCA default is a value that is parsed from DisCo
and then written out to the hardware if no user value has superceded
it. Add a helper function that will iterate through all the SDCA
Controls and write out any default values. After these have been written
out once they will exist in the cache and that will take care of any
user values superceeding them. The code here also writes out any
Controls with a fixed value as there is only one available value for
these Controls there is no point in allowing the user to select them,
simply treat them similarly to a default.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.dev>
Link: https://patch.msgid.link/20250217140159.2288784-5-ckeepax@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>