ASoC: Add SPDX ids to many soc files

ASoC: Add SPDX ids to many soc files

Add appropriate SPDX-License-Identifier lines to the
the remaining files that are missing such lines in the
sound/soc directory, and in a few other miscelaneous files.
Remove boilerplate license text.

Signed-off-by: Tim Bird <tim.bird@sony.com>
Link: https://patch.msgid.link/20260217190837.165504-1-tim.bird@sony.com
Signed-off-by: Mark Brown <broonie@kernel.org>