No current users and it's the last user of MICBIAS_E().
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: NDong Aisheng <dong.aisheng@linaro.org>
Acked-by: NZeng Zhaoming <zengzm.kernel@gmail.com>
Tested-by: NShawn Guo <shawn.guo@linaro.org>