commit 6a556039 upstream.

RV250 found on ppc embedded boards.

Cc: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>