Added properties to enable ITS feature and define qemu system
address space memory in gicv3 common,setup distributor and
redistributor registers to indicate LPI support.

Signed-off-by: Shashi Mallela <shashi.mallela@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Tested-by: Neil Armstrong <narmstrong@baylibre.com>
Message-id: 20210910143951.92242-6-shashi.mallela@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>