dt-bindings: display/msm: dp-controller: Add SM6150

dt-bindings: display/msm: dp-controller: Add SM6150

Add DisplayPort controller binding for Qualcomm SM6150 SoC.
SM6150 uses the same controller IP as SM8150.
Declare 'qcom,sm6150-dp' as a fallback compatible to
'qcom,sm8150-dp' and 'qcom,sm8350-dp' for consistency with existing
bindings and to ensure correct matching and future clarity.

Signed-off-by: Xiangxu Yin <xiangxu.yin@oss.qualcomm.com>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Patchwork: https://patchwork.freedesktop.org/patch/674893/
Link: https://lore.kernel.org/r/20250916-add-dp-controller-support-for-sm6150-v3-1-dd60ebbd101e@oss.qualcomm.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>