ASoC: max98363: Make soc_codec_dev_max98363 static

smatch reports
sound/soc/codecs/max98363.c:392:39: warning: symbol
  'soc_codec_dev_max98363' was not declared. Should it be static?

This variable is only used in one file so should be static.

Signed-off-by: Tom Rix <trix@redhat.com>
Link: https://lore.kernel.org/r/20230406152300.1954292-1-trix@redhat.com


Signed-off-by: Mark Brown <broonie@kernel.org>