drm/radeon/kms/atom/pm: rework power mode parsing

On pre-r6xx, the power mode array is usually ordered:
low
...
high
default

On r6xx+:
default
low
...
high

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