hack: ASoC: wm8962: Trigger mic detection on out_pga_event

The SND_SOC_DAPM_POST_REG event is called when the headphone output path
is being (de)configured, which is a good place to hack trigger detection
in until we get a dedicated card driver.
2 jobs for mic-det in 78 minutes and 37 seconds (queued for 6 seconds)