arm64: dts: marvell: Change core numbering in AP806 thermal-node

When adding thermal nodes, the CPUs have been named from 1 to 4 while
usually everywhere else they are referred as 0-3. Let's change this to
be consistent with later changes when we will use CPUfreq and CPU
phandles as cooling devices to avoid inconsistencies in the nodes
numbering.

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