ARM: dts: msm: add support for micbias as on demand supply

Micbias and USB share the same power rail. When USB is
disconnected, mic is not working. Enable micbias on external
codec as on demand power supply.

Change-Id: Ibc68f6d5ed4b3502be732ccef8b75b8d2cacd223
Signed-off-by: Laxminath Kasam <lkasam@codeaurora.org>