clk: renesas: rzg2l: Move the DEF_MUX array size calc into the macro

We only ever use ARRAY_SIZE() to populate the number of parents, so
move this into the macro to always detect it automatically. This
also makes the tables of clocks a little simpler.
Similarly for the DEF_SD_MUX macro.

Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
Link: https://lore.kernel.org/r/20220503115557.53370-6-phil.edworthy@renesas.com


Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>