ASoC: wcd9xxx: Prevent disabling of internal micbias

If recording is also using internal micbias, then after recording
ends, the dapm widget power down callback will reset the state of
internal micbias in codec register. To avoid such issues make sure
internal micbias is enabled while headset detection, button press
detection and polling.

CRs-fixed: 565636
CRs-fixed: 565389
Change-Id: I3c98eae4b958fbf3e0050bc8aa49844755f4c21d
Signed-off-by: Simmi Pateriya <simmip@codeaurora.org>