clk: sunxi: sun6i-a31-apb0-gates: Add A23 APB0 support

This patch adds "allwinner,sun8i-a23-apb0-gates-clk", a A23 specific
compatible to the sun6i-a31-apb0-gates clock driver, along with the
gate bitmap.

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