arm64: dts: renesas: r8a774e1: Add VSP instances

The RZ/G2H (R8A774E1) has 6 VSP instances.

Based on the work done for r8a7795 SoC.

Signed-off-by: Marian-Cristian Rotariu <marian-cristian.rotariu.rb@bp.renesas.com>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20200810092208.27320-3-prabhakar.mahadev-lad.rj@bp.renesas.com


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