arm64: defconfig: Enable R-Car S4-8

Enable the Renesas R-Car S4-8 (R8A779F0) SoC in the ARM64 defconfig.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/20211201073308.1003945-15-yoshihiro.shimoda.uh@renesas.com


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