clk: sunxi-ng: Fix missing CLK_SET_RATE_PARENT in ccu-sun4i-a10.c

When using cpufreq-dt with default govenor other than "performance"
system freezes while booting.
Adding CLK_SET_RATE_PARENT | CLK_IS_CRITICAL to clk_cpu fixes the
problem.

Tested on Cubietruck (A20).

Fixes: c84f5683 ("clk: sunxi-ng: Add sun4i/sun7i CCU driver")
Acked-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Alexander Syring <alex@asyring.de>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>