ASoC: wcd-mbhc: Disable micbias internal pull-up after headphone detected

Micbias2 internal pull-up remains enabled even after headphone is detected.
This results in power issues. Disable pull up after insertion detection.

Change-Id: I335dbb498192738fc282421d92510400a661cf0c
Signed-off-by: Vatsal Bucha <vbucha@codeaurora.org>