arm64: defconfig: enable R8A77990 SoC

Enable the Renesas R-Car E3 (R8A77990) SoC in the ARM64 defconfig.
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

arch/arm64/configs/defconfig

@@ -53,6 +53,7 @@ CONFIG_ARCH_R8A7796=y
 CONFIG_ARCH_R8A77965=y
 CONFIG_ARCH_R8A77970=y
 CONFIG_ARCH_R8A77980=y
+CONFIG_ARCH_R8A77990=y
 CONFIG_ARCH_R8A77995=y
 CONFIG_ARCH_STRATIX10=y
 CONFIG_ARCH_TEGRA=y