ASoC: cx2072x: remove set but not used variable 'is_right_j '

Fixes gcc '-Wunused-but-set-variable' warning:

sound/soc/codecs/cx2072x.c: In function cx2072x_config_i2spcm:
sound/soc/codecs/cx2072x.c:679:6: warning: variable is_right_j set but not used [-Wunused-but-set-variable]

It's never used and can be removed.

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Mark Brown <broonie@kernel.org>