clk: sunxi-ng: add support for Allwinner H3 DE2 CCU

Allwinner H3 features a DE2 CCU like the one on A83T, however the
parent of the clocks is the DE module clock, not the PLL_DE clock.

Add support for it.

Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Signed-off-by: Chen-Yu Tsai <wens@csie.org>