drm/amd/display: TMDS Fallback transition

[Why]
HDMI requires fallback to TMDS by redetection
in order to switch PHY settings.
This avoids black out when link training fail
during mode setting, link quality update,
disable driver sequence.

[How]
Allow driver to redetect HDMI displays
based on retraining or fallback mechanism.

Signed-off-by: Chris Park <Chris.Park@amd.com>
Reviewed-by: Aric Cyr <Aric.Cyr@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>