ASoC: Intel: sof_sdw_rt700: add codec prefix

Somehow for this codec we never used any prefix for the controls,
likely because the test platform has a single SoundWire device.

Follow the convention and use the codec prefix across the board to
avoid possible conflicts.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Link: https://lore.kernel.org/r/20200923080514.3242858-6-kai.vehmanen@linux.intel.com


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