ASoC: codecs: msm8916-wcd-analog: add MBHC support

MBHC (MultiButton Headset Control) support is available in pm8921 in two
blocks, one to detect mechanical headset insertion and removal and other
block to support headset type detection and 5 button detection and othe
features like impedance calculation.

This patch adds support to:
1> Support to NC and NO type of headset Jacks.
2> Mechanical insertion and detection of headset jack.
3> Detect a 3 pole Headphone and a 4 pole Headset.
4> Detect 5 buttons.

Tested it on DB410c with Audio Mezz board with 4 pole and 3 pole
headset/headphones.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Tested-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
Signed-off-by: Mark Brown <broonie@kernel.org>