arm64: dts: renesas: r8a774e1: Add cpuidle support for CA5x cores

Enable cpuidle (core shutdown) support for RZ/G2H CA5x cores.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20200827145315.26261-3-prabhakar.mahadev-lad.rj@bp.renesas.com


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