ARM: sun5i: a10s: Add support for the High Speed Timers

The Allwinner A10s has support for two high speed timers. Now that we
have a driver to support it, we can enable them in the device tree.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Tested-by: Emilio López <emilio@elopez.com.ar>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>