ASoC: wcd: handle micbias and current source properly

Micbias is getting disabled during detection on
in correct plug work. Due to this buttons do
not work on the headset on other side of extn
cable. Also, since micbias is kept enabled for
the polling period, the current source doesn't
get enabled while reporting headset. And since,
micbias is getting disabled in correct work,
this results in button not getting detected on
direct insertion of jack also.

CRs-Fixed: 698473
Change-Id: I1dd7298c93ac00e73450db4bbb2e63d7ab235a6b
Signed-off-by: Simmi Pateriya <simmip@codeaurora.org>