arm64: dts: renesas: r8a77965: Add DRIF support

Add the DRIF controller nodes for r8a77965 (a.k.a. R-Car M3-N).

Signed-off-by: Fabrizio Castro <fabrizio.castro.jz@renesas.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20201021135332.4928-6-fabrizio.castro.jz@renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>