radeon_hd: Improve tracing; implement older DCE3 DP training.

* Implement older DCE 3 DisplayPort Training Service.

radeon_hd: AtomBIOS version bump. Encoder work.

* Now pulling in latest amdgpu atombios.h headers
* Lots of DisplayPort cleanup and removal of legacy stuff
* Add obsolete atombios header for things that disappear
(amdgpu doesn't support older cards like we do)
* Introduce new code to support later encoder tables
* Drop radeon-specific encoder service from common dp_info
* Tested on HD 5450 hdmi