arm64: dts: qcom: sm8450: add display hardware devices

Add devices tree nodes describing display hardware on SM8450:
- Display Clock Controller
- MDSS
- MDP
- two DSI controllers and DSI PHYs

This does not provide support for DP controllers present on SM8450.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>