arm64: dts: msm8996: Add UFS PHY reset controller

Add the reset controller for the UFS controller, and wire it up
so that the UFS PHY can initialize itself without relying on
implicit sequencing between the two drivers.

Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Evan Green <evgreen@chromium.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Andy Gross <agross@kernel.org>