arm64: dts: msm8996: Add device node for qcom qmp-phy for usb

Adding required device node for USB3 QMP phy present on
msm8996 chipset to enable support for the same. This phy
provides super speed usb functionality for dwc3 controller
on msm8996.

Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>