drm/amd/display: Adding HDMI SCDC DEVICE_ID define

[Why && How]
We will need to differentiate vendor behavior in the future.

Reviewed-by: Chris Park <Chris.Park@amd.com>
Acked-by: Alan Liu <HaoPing.Liu@amd.com>
Signed-off-by: Leo Ma <hanghong.ma@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>