arm64: dts: marvell: add thermal-zone node in ap806 DTSI file

Add a thermal-zone node and fill in all the sensors available in an
ap806 (one in the IC plus one per CPU).

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>