Hardware doesn't seem to work correctly, just block userspace in this case.

v2: add missing defines

Bugs: https://bugs.freedesktop.org/show_bug.cgi?id=85320Signed-off-by: Christian König <christian.koenig@amd.com>
CC: stable@vger.kernel.org
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>