ASoC: Intel: kbl_da7219_max98357a: remove unused variable 'constraints_16000' and 'ch_mono'

sound/soc/intel/boards/kbl_da7219_max98357a.c:343:48:
 warning: constraints_16000 defined but not used [-Wunused-const-variable=]
sound/soc/intel/boards/kbl_da7219_max98357a.c:348:27:
 warning: ch_mono defined but not used [-Wunused-const-variable=]

They are never used, so can be removed.
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20191224140237.36732-1-yuehaibing@huawei.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/intel/boards/kbl_da7219_max98357a.c

@@ -336,19 +336,6 @@ static struct snd_soc_ops kabylake_dmic_ops = {
 	.startup = kabylake_dmic_startup,
 };
 
-static const unsigned int rates_16000[] = {
-	16000,
-};
-
-static const struct snd_pcm_hw_constraint_list constraints_16000 = {
-	.count = ARRAY_SIZE(rates_16000),
-	.list  = rates_16000,
-};
-
-static const unsigned int ch_mono[] = {
-	1,
-};
-
 SND_SOC_DAILINK_DEF(dummy,
 	DAILINK_COMP_ARRAY(COMP_DUMMY()));