drm/radeon/dpm: drop clk/voltage dependency filters for SI

Not sure this was ever necessary for SI, was just done
to be on the safe side.

bug:
https://bugs.freedesktop.org/show_bug.cgi?id=69721



Reviewed-by: Alexandre Demers <alexandre.f.demers@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>