drm/amd/display: Add HDMI member to DTO

[Why]
For Pixel Rate control, when on HDMI, HDMI DTO
should be selected instead of DP DTO.

[How]
Add HDMI member to dtbclk_dto_params, so it can be used tell apart HDMI
and DP DTO in the future.

Reviewed-by: Alvin Lee <Alvin.Lee2@amd.com>
Acked-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Chris Park <chris.park@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>