ASoC: wcd937x: Fix audio distortion issue during headset record

Audio is distorted during first 3 secs on headset record
while doing device switch from dmic to headset mic.
Disable BCS before slow insertion detection and enable it
afterwards to resolve the issue.

Change-Id: Icb18a0b5decb0c0bd9959bce7cced70a27566d41
Signed-off-by: Vatsal Bucha <vbucha@codeaurora.org>