dt-bindings: arm: Convert Marvell AP80x System Controller to DT schema

dt-bindings: arm: Convert Marvell AP80x System Controller to DT schema

Convert the Marvell AP80x System Controller binding to DT schema format.

There's not any specific compatible for the whole block which is a
separate problem, so just the child nodes are documented. Only the
pinctrl and clock child nodes need to be converted as the GPIO node
already has a schema.

Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://patch.msgid.link/20251014153040.3783896-1-robh@kernel.org
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>