arm64: dts: qcom: msm8996: Add ufs related nodes

Add the UFS QMP phy node and the UFS host controller node, now that we
have working UFS and the necessary clocks in place.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>