ASoC: codecs: ak4458: Remove set but never checked variable 'ret'

ASoC: codecs: ak4458: Remove set but never checked variable 'ret'

Looks as though the result of snd_soc_update_bits() has never been checked.

Fixes the following W=1 kernel build warning(s):

sound/soc/codecs/ak4458.c: In function ‘ak4458_set_dai_mute’:
sound/soc/codecs/ak4458.c:408:16: warning: variable ‘ret’ set but not
used [-Wunused-but-set-variable]

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Cc: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Cc: Junichi Wakasugi <wakasugi.jb@om.asahi-kasei.co.jp>
Cc: Mihai Serban <mihai.serban@nxp.com>
Link: https://lore.kernel.org/r/20200709162328.259586-11-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>