clk: sunxi-ng: div: Support finding closest rate

Add initalization macros for divisor clocks with mux
(SUNXI_CCU_M_WITH_MUX) to support finding the closest rate. This clock
type requires the appropriate flags to be set in the .common structure
(for the mux part of the clock) and the .div part.

Acked-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>
Link: https://lore.kernel.org/r/20230807-pll-mipi_set_rate_parent-v6-9-f173239a4b59@oltmanns.dev


Signed-off-by: Chen-Yu Tsai <wens@csie.org>