clk: renesas: r8a77990: Add DAB clock

This patch adds the DAB clock to the R8A77990 SoC.

Signed-off-by: Fabrizio Castro <fabrizio.castro.jz@renesas.com>
Link: https://lore.kernel.org/r/20210225225147.29920-2-fabrizio.castro.jz@renesas.com


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