arm64: dts: marvell: Add NAND flash controller to AC5

The AC5/AC5X SoC has a NAND flash controller (NFC). Add this to
the base SoC dtsi file as a disabled node. The NFC integration
on the AC5/AC5X only supports SDR timing modes up to 3 so requires a
dedicated compatible property so this limitation can be enforced.

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>