ARM: dts: sunxi: Remove overclocked/overvoltaged OPP

Without proper regulator support for individual boards, it is dangerous
to have overclocked/overvoltaged OPPs in the list. Cpufreq will increase
the frequency without the accompanying voltage increase, resulting in
an unstable system.

Remove them for now. We can revisit them with the new version of OPP
bindings, which support boost settings and frequency ranges, among
other things.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>