ASoC: Intel: sof-rt5682: fix for codec button mapping

The RT5682 codec button mapping, initially copied from the DA7219 one,
needs to be corrected.

Signed-off-by: Sathya Prakash M R <sathya.prakash.m.r@intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>