The VExpress development platform has an external expansion bus which
can be used for additional hardware (e.g. LogicTile Express daughter
boards).

Add this bus to the VExpress CoreTile device-trees.The bus is described
for a CoreTile occupying site 1.
Acked-by: Liviu Dudau <Liviu.Dudau@arm.com>
Signed-off-by: Brian Starkey <brian.starkey@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>