ASoC: samsung: i2s: mark OF related data as maybe unused

ASoC: samsung: i2s: mark OF related data as maybe unused

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

  sound/soc/samsung/i2s.c:1646:42: warning: ‘i2sv5_dai_type_i2s1’ defined but not used [-Wunused-const-variable=]
  sound/soc/samsung/i2s.c:1639:42: warning: ‘i2sv7_dai_type’ defined but not used [-Wunused-const-variable=]

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Sylwester Nawrocki <snawrocki@kernel.org>
Link: https://lore.kernel.org/r/20201125164452.89239-36-krzk@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>