usb: qmp: phy: Turn ON PIPE3 clock branch before QMP PHY power up

SW_PWRDN_B (BIT:0) of USB3_PHY_POWER_DOWN_CONTROL register is active
low signal. Resetting QMP PHY keeps it into power down state only.
Hence enable PIPE3 clock branch before powering up QMP PHY.

Change-Id: I64d2b4482504f7a2f7c6e5ffd53a68ceca7543ba
Signed-off-by: Mayank Rana <mrana@codeaurora.org>