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

Add required device node for QMP phy based 3-lane PCIe phy
present on msm8996 chipset to enable support for the same.

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