aarch64: update to latest Mach-Virt addresses

until we have the ACPI ported, we have to follow mach-virt.
Its addresses for the GIC have been recently changed.

Signed-off-by: Claudio Fontana <claudio.fontana@huawei.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>