drm/radeon/kms: remove rv100 bios connector quirk

Some RV100 cards with 2 VGA ports show up with DVI+VGA, however
some boards with DVI+VGA have the same subsystem ids. Better
to have a VGA port show up as DVI than having a non-useable
DVI port.

reported by DHR in irc.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>