arm64: dts: renesas: r8a774c0: Add secondary CA53 CPU core

Add a device node for the second Cortex-A53 CPU core on the Renesas
RZ/G2E (a.k.a r8a774c0) SoC, and adjust the interrupt delivery masks
for the ARM Generic Interrupt Controller and Architectured Timer.

Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>