arm64: dts: renesas: r8a774b1: Add all MSIOF nodes

Add the device nodes for all MSIOF SPI controllers on the RZ/G2N
SoC (a.k.a. r8a774b1).

Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Link: https://lore.kernel.org/r/1570178133-21532-6-git-send-email-fabrizio.castro@bp.renesas.com


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