drm/amd: Add USBC connector ID

[ Upstream commit c5c948aa894a831f96fccd025e47186b1ee41615 ]

[Why&How] Add a dedicated AMDGPU specific ID for use with
newer ASICs that support USB-C output

Signed-off-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>