commit 5e5c21ca upstream.

Check the that ring we are using for copies is functional
rather than the GFX ring.  On newer asics we use the DMA
ring for bo moves.
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>