ARM: dts: armada-xp: enable L2 cache parity and ecc on db-xc3-24g4xg

Enable L2 cache parity and ECC on the db-xc3-24g4xg board so that cache
operations are protected and errors can be flagged to the EDAC
subsystem.

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