drm/radeon: remove 0x4243 pci id

commit 63a50780 upstream.

0x4243 is a PCI bridge, not a GPU.

Fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=33815



Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>