The highest supported frequency (1.2GHz) requires to "overvolt" the CPU.
However, some boards still do not have the cpu-supply DT property in the
cpu DT node which means that the CPU will always run with the same input
voltage but try to run at 1.2GHz frequency. This is the source of
(experienced) CPU crashes.

Remove the OPP which requires overvolting the CPU until all boards have
a cpu-supply property.

Fixes: 03749eb8 ("ARM: dts: sun8i: add opp-v2 table for A33")
Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>