arm64: dts: renesas: r8a779g0: Add secondary CA76 CPU cores

Complete the description of the Cortex-A76 CPU cores and L3 cache
controllers on the Renesas R-Car V4H (R8A779G0) SoC, including CPU
topology and PSCI support for enabling CPU cores.

R-Car V4H has 4 Cortex-A76 cores, grouped in 2 clusters.

Based on a patch in the BSP by Takeshi Kihara.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/ccb55458bd87f8ba70d28c61bcc254f22184824c.1668429870.git.geert+renesas@glider.be