ASoC: uniphier: mark OF related data as maybe unused

ASoC: uniphier: mark OF related data as maybe unused

The driver can be compile tested with !CONFIG_OF making certain data
unused:

  sound/soc/uniphier/aio-ld11.c:375:34: warning: ‘uniphier_aio_of_match’ defined but not used [-Wunused-const-variable=]
  sound/soc/uniphier/evea.c:554:34: warning: ‘evea_of_match’ defined but not used [-Wunused-const-variable=]

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20201125164452.89239-14-krzk@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>