MIPS: mscc: Add ocelot PCB123 device tree

Add a device tree for the Microsemi Ocelot PCB123 evaluation board.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Allan Nielsen <Allan.Nielsen@microsemi.com>
Cc: linux-mips@linux-mips.org
Cc: devicetree@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/18856/


Signed-off-by: James Hogan <jhogan@kernel.org>