usb: phy: qmp: Add support to enable/disable USB QMP PHY clocks

Currently few USB QMP PHY clocks are enable always on USB cable
disconnect and entering into USB low power mode. Due to this
XO/VDD Min shutdown is not happening. This change adds support
to enable/disable USB QMP PHY clocks based on USB cable status
before going into USB low power mode.

Change-Id: Ibad5759178f98d94ffcc84b9b1f647f478a980c6
Signed-off-by: Mayank Rana <mrana@codeaurora.org>