arm64: defconfig: Enable R8A779G0 SoC

Enable the Renesas R-Car V4H (R8A779G0) SoC in the ARM64 defconfig.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/eb672fad7c9a340812079a07539d670f42f4ad41.1654855105.git.geert+renesas@glider.be