drm/msm display updates for 6.9 (1st round)

Core:

• Correct bindings for MSM8976 and SM8650 platforms
• Start migration of MDP5 platforms to DPU driver

DPU:

• Improve DSC allocation, fixing several important corner cases
• Add support for SDM630/SDM660 platforms
• Simplify dpu_encoder_phys_ops
• Apply fixes targeting DSC support with a single DSC encoder
• Apply fixes for HCTL_EN timing configuration

DP:

• Refactor parser and power submodules

DSI:

• Clean up obsolete set_split_display support
• Update DSC documentation

MDP5:

• Clean up obsolete set_split_display support