drm/radeon/kms: add new BTC PCI ids

commit a2bef8ce826dd1e787fd8ad9b6e0566ba59dab43 upstream.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>