ASoC: wcd9330: add support for impedance detection

Different headphones have different impedance that results in
volume level difference on ears, as lower impedance headphone
will have higher volume with the same gain on PAs while the
headphone with higher impedance will have lower volume.
Add support for impedence detection for WCD9330 codec which
can be used to adjust the headphone volume levels.

Change-Id: I1f785ca040f83e45e2f999fd124ce2000e9cba44
Signed-off-by: Banajit Goswami <bgoswami@codeaurora.org>