drm/amd/display: Refactor debugfs entries for all connectors

[Why]
Debugfs entries being moved from DP/eDP only to be available
on all connectors are cluttering the code.

[How]
Refactor the registration of these debugfs entries.

Signed-off-by: Stylon Wang <stylon.wang@amd.com>
Acked-by: Bindu Ramamurthy <bindu.r@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>