ASoC: Intel: glk_rt5682_max98357a: removed unused variables

Fix GCC warning with W=1

sound/soc/intel/boards/glk_rt5682_max98357a.c:256:48: warning:
‘constraints_channels’ defined but not used [-Wunused-const-variable=]

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20200113210428.27457-5-pierre-louis.bossart@linux.intel.com


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