ASoC: wcd9320: Fix micbias setting for MAD

For Microphone Activity Detection (MAD) to work properly, it is required
to update the micbias setting correctly to indicate the micbias is
external or internal. Correct the MAD micbias settings to account for
type of micbias (internal or external).

CRs-fixed: 684818
Change-Id: If209f9e4ad971a25fd28848ba7ba297c4f3dbf06
Signed-off-by: Bhalchandra Gajare <gajare@codeaurora.org>