ASoC: wcd9xxx: Do not use current source if micbias is already enabled

Some targets share the same micbias for handset mic and headset mic.
When any recording is in progress from handset mic and if headset
is inserted, we shouldn't be using current source for the detection
as the micbias is already enabled. Check if micbias is already enabled
or not and if it is already enabled, detect the headset insertion using
micbias and not with current source.

CRs-Fixed: 572295
Change-Id: I269c2320ed735fa07f6b77ebffe4d2a1a8163da9
Signed-off-by: Phani Kumar Uppalapati <phaniu@codeaurora.org>