arm64: dts: qcom: Add display support for QCS615

arm64: dts: qcom: Add display support for QCS615

Add display MDSS and DSI configuration for QCS615 platform.
QCS615 has a DP port, and DP support will be added in a later patch.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Li Liu <li.liu@oss.qualcomm.com>
Signed-off-by: Fange Zhang <fange.zhang@oss.qualcomm.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250903-add-display-support-for-qcs615-platform-v8-1-7971c05d1262@oss.qualcomm.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>