- disable gui idle interrupt use
  Seems to hang some r5xx chips
- move vbl range check into
  existing vbl check function in
  radeon_pm.c
- disable crtc mc acccess for the
  whole reclocking process
Signed-off-by: NAlex Deucher <alexdeucher@gmail.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>