ARM64: dts: Add special compatibles for the Turris Mox

These special compatibles are added to the Marvell Armada 3720
Turris Mox in order to be able to special-case and avoid
warnings on the non-standard nodenames that are ABI on this
one board due to being used in deployed versions of U-Boot.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>