drm: radeon: only allow specific type-3 packetss through verifier

only allow specific type-3 packets to pass the verifier instead of all for r100/r200 as others might be unsafe (r300 already does this), and add checking for these we need but aren't safe. Check the RADEON_CP_INDX_BUFFER packet on both r200 and r300 as it isn't safe neither.

Signed-off-by: Dave Airlie <airlied@linux.ie>