clocksource: sun4i: Increase a bit the clock event and sources rating

We want to keep this driver as the default provider of the clock events
and source, yet some other driver might fit in the "desired" category of
ratings. Hence, we need to increase a bit the rating so that we can have
more flexibility in the ratings we choose.

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>