ASoC: msm8916-wcd-analog: Fix selected events for MIC BIAS External1

MIC BIAS External1 sets pm8916_wcd_analog_enable_micbias_ext1()
as event handler, which ends up in pm8916_wcd_analog_enable_micbias_ext().

But pm8916_wcd_analog_enable_micbias_ext() only handles the POST_PMU
event, which is not specified in the event flags for MIC BIAS External1.
This means that the code in the event handler is never actually run.

Set SND_SOC_DAPM_POST_PMU as the only event for the handler to fix this.

Fixes: 585e881e

 ("ASoC: codecs: Add msm8916-wcd analog codec")
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Link: https://lore.kernel.org/r/20200111164006.43074-2-stephan@gerhold.net
Signed-off-by: Mark Brown <broonie@kernel.org>