drm/radeon/kms/r6xx+: voltage fixes

0xff01 is not an actual voltage value, but a flag
for the driver.  If the power state as that value,
skip setting the voltage.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
4 files changed