AMDGPU DC Display Code Ported To GCN 1.0 "Southern Islands" GPUs

The AMDGPU DC "Display Code" stack formerly known as DAL that's been in the mainline kernel the past several releases might soon see support for GCN 1.0 "Southern Islands" GPUs. This is the big display code stack necessary for atomic mode-setting, FreeSync/Adaptive-Sync, HDMI/DP audio, and other modern display features. When AMD brought up this DC stack, they hadn't brought it back to GCN 1.0 since for those original GCN GPUs they by default still use the Radeon DRM driver. But now they might soon see AMDGPU DC support...