drm/amd/display: Implement DPIA link configuration

[Why]
Training settings need to be applied to DPIA link at start of each
training loop. Note: FEC readiness should be configured before link
training while FEC enablement should be configured once training is
complete.

[How]
- Implement DPIA link configuration function.
- Account for dynamically assigned link encoders during link
configuration.

Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Wayne Lin <Wayne.Lin@amd.com>
Acked-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Jimmy Kizito <Jimmy.Kizito@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>