ASoC: wcd9xxx: Add support to enable or disable impedance detection

Add support to enable or disable impedance detection
using kernel module parameter. This gives flexibility
for the user to enable or disable this feature.

Change-Id: Ieeb724241f08b861c1bf9a9c06b59d4827ecfd20
Signed-off-by: Phani Kumar Uppalapati <phaniu@codeaurora.org>