ASoC: wm8988: fix typo in wm8988_right_line_controls

sound/soc/codecs/wm8988.c:270:30: warning:
 wm8988_rline_enum defined but not used [-Wunused-const-variable=]

wm8988_rline_enum should be used in wm8988_right_line_controls.

Reported-by: Hulk Robot <hulkci@huawei.com>
Fixes: 5409fb4e ("ASoC: Add WM8988 CODEC driver")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190822143608.59824-1-yuehaibing@huawei.com


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