ASoC: wcd9xxx: Enhance class H controller to support dynamic CP voltage

Codecs can operate at a lower voltage for vdd_buck, whereas
this voltage source being shared, it is not guaranteed that the
codec will always receive exactly the requested voltage. Add support
to class H controller to handle dynamic switching of the chargepump
voltage.

Change-Id: I68f93e0b070ec51db9b958f56c797edb5cbe0c85
Signed-off-by: Bhalchandra Gajare <gajare@codeaurora.org>

Conflicts:
	sound/soc/codecs/wcd9306.c