ASoC: wm8995: Replace usage deprecated MUX/ENUM macros

SND_SOC_DAPM_VIRT_MUX and SOC_DAPM_ENUM_VIRT are deprecated and merely an alias
for SND_SOC_DAPM_MUX and SOC_DAPM_ENUM. Replace the deprecated macros so we can
eventually remove their definition.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>