usb: phy: qusb: Add support to configure QUSB PHY regulator

Currently QUSB PHY driver is enabling vdd18, vdd33 and vdd related
regulator without setting optimum voltage and current requirement
for QUSB PHY to be in operational mode. Hence this change adds
required voltage/current configuration for those regulators when
those are enabled and disabled.

Change-Id: I7e281ecb5f8255d85bc53048f1eab2a789a4be99
Signed-off-by: Mayank Rana <mrana@codeaurora.org>