drm/radeon/kms: r600/r700 don't test ib if ib initialization fails

If ib initialization failed don't try to test ib as it will result
in an oops (accessing NULL ib buffer ptr).

Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@linux.ie>
2 files changed