ASoC: rt1011: revert 'I2S Reference' to SOC_ENUM_EXT

Revert 'I2S Reference' to SOC_ENUM_EXT because the settings are specific
for some platforms, the default setting for 'I2S Reference' does nothing,
only some SoC platform need to configure it.
Previous 'I2S Reference' in SOC_ENUM format only toggles one bit of
RT1011_TDM1_SET_1 register, which isn't enough for specific platform.

Signed-off-by: Jack Yu <jack.yu@realtek.com>
Link: https://lore.kernel.org/r/20211111091705.20879-1-jack.yu@realtek.com
Signed-off-by: Mark Brown <broonie@kernel.org>