The A23 has an almost identical PRCM clock tree. The difference in
the APB0 clock is the smallest divisor is 1, instead of 2.

This patch adds a separate sun8i-a23-apb0-clk driver to support it.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>