Add support for GICv2 virtualization extensions by mapping the necessary
I/O regions and connecting the maintenance IRQ lines.

Declare those additions in the device tree and in the ACPI tables.
Signed-off-by: NLuc Michel <luc.michel@greensocs.com>
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Message-id: 20180727095421.386-21-luc.michel@greensocs.com
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>