ASoC: max98926: remove two unused variables

ASoC: max98926: remove two unused variables

sound/soc/codecs/max98926.c:28:26: warning:
 max98926_dai_txt defined but not used [-Wunused-const-variable=]
sound/soc/codecs/max98926.c:23:27: warning:
 max98926_boost_current_txt defined but not used [-Wunused-const-variable=]

They are never used, so can be removd.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190808143215.65904-1-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>