arm64: dts: marvell: rename armada-ap806 XOR nodes

Node names should not contain an instance number, the unit address
serves to distinguish nodes of the same name. So rename the XOR nodes
to just xor@<address>.

Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
[Thomas:
 - remove labels, they are really not needed for XOR engines.
 - remove the Fixes: tag, as this is not a fix.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>