arm64: dts: renesas: r8a774c0: Add PFC support

Add PFC support to the RZ/G2E (a.k.a. r8a774c0) SoC specific
device tree.

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>