ASoC: rt711-sdca-sdw: add readable for SDW_SDCA_CTL() registers

SDW_SDCA_CTL() registers are used but are not set to readable.

Fixes: 7ad4d237 ('ASoC: rt711-sdca: Add RT711 SDCA vendor-specific driver')
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20210607222239.582139-15-pierre-louis.bossart@linux.intel.com


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