arm64: dts: renesas: r8a779g0: Add CA76 operating points

Add operating points for running the Cortex-A76 CPU cores on R-Car V4H
at various speeds, up to the Normal (1.7 GHz) performance mode.

Based on a patch in the BSP by Tho Vu.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/8afb32f5dc123ebf2b941703483152ff0992191d.1668429870.git.geert+renesas@glider.be