dts:mc3:hdmi: Add onboard HDMI support

At the moment there is a problem with the HDMI hot plug detection (HPD)
in combination with the eARC. The HPD only works correctly when
the EARC_N_HPD signal is disconnected. Simply enabling or disabling the
xcvr (eARC) controller does not result in a valid HPD.
HDMI works when the eARC is not connected.
The 5V fault detection is currently not supported.

BCS 746-000949