clk: sunxi: staticize structures and arrays

There are some structs and arrays on the driver that are not used
anywhere else. Let's mark them as static.

Signed-off-by: Emilio López <emilio@elopez.com.ar>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>