clk: sunxi-ng: Allow DE clock to set parent rate

DE2/DE3 mixers have to run at specific frequency in order to work
optimally. This wasn't actually possible for some SoCs because "de"
clock wasn't allowed to adjust parent rate.

Add CLK_SET_RATE_PARENT flag to all "de" clocks which didn't have it
yet.

Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>