drm/amd/display: Fix IGT link training failure on Replay panel

drm/amd/display: Fix IGT link training failure on Replay panel

[Why]
IGT link-training-configs test fails to set the link rate on Replay panels
because some link rate types are not supported in debugfs. As a result,
debugfs treats these link rates as invalid, causing the IGT test to fail.

[How]
Add missing link rate types to resolve this issue.

Reviewed-by: ChiaHsuan Chung <chiahsuan.chung@amd.com>
Signed-off-by: Ray Wu <ray.wu@amd.com>
Signed-off-by: Wayne Lin <wayne.lin@amd.com>
Tested-by: Dan Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>