fix(fvp_ve): fdts: Fix vexpress,config-bus subnode names

The arm,vexpress,config-bus DT binding restricts the possible (sub)node
names.
Adjust the current node names, to drop the unneeded address specifier,
and make the node names binding compliant.

Change-Id: Ic48c6969268c960ce92c8ec3a756ed1d89e61b08
Signed-off-by: Andre Przywara <andre.przywara@arm.com>