ARM: dts: msm: add headset micbias type checking

Add the headset micbias type property and check it in MBHC driver.
If the external micbias is used for headset mic, don't enable the
internal micbias during headset type detection, otherwise the type
detection will be unreliable.

Change-Id: Id29bb61c581f8ecf845e84e4a3d2f3df53b1435b
Signed-off-by: Walter Yang <yandongy@codeaurora.org>