drm/radeon: add quirk for RV100 board

vbios says external TMDS while the board is actually
internal TMDS.

fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=60037

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
1 file changed