Juno uses a 1:1 mapping between CPU and PCI addresses for IO. First,
that will trip devices that cannot use more than 16 bits of addresses
for IO, second it is un-necessary as the system can handle zero-based
PCI addresses just fine.
Change the mapping to start IO bus addresses from zero.
Signed-off-by: Liviu Dudau <Liviu.Dudau@foss.arm.com>