ARM: dts: sunxi: Use sun4i-a10-apb1-clk for sun6i/sun8i apb2 clocks.

The apb2 clocks are actually the same as apb1 clocks on the other sunxi
platforms, hence compatible with "allwinner,sun4i-a10-apb1-clk".

Update the dtsi to use the new unified apb1 clk.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>