clk: renesas: rzg2l: Add read only versions of the clk macros

This just makes the clk tables easier to read.

Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
Link: https://lore.kernel.org/r/20220503115557.53370-7-phil.edworthy@renesas.com


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