usb: phy: qusb: Set the voltage to regulator according to soc capacity

Register to power supply framework to get soc capacity.
Change the voltage that needs to be set to regulator
according to soc capacity, this helps in battery optimization
and also stabilizing the performance.

Change-Id: Ide49027edc941eb163ffde4ded9fef19d144baa4
Signed-off-by: Rohith Kollalsi <rkollals@codeaurora.org>