hw/arm/virt-acpi-build: Present the GICR structure properly for GICv4

hw/arm/virt-acpi-build: Present the GICR structure properly for GICv4

With the introduction of the new TCG GICv4, build_madt() is badly broken
as we do not present any GIC Redistributor structure in MADT for GICv4
guests, so that they have no idea about where the Redistributor
register frames are. This fixes a Linux guest crash at boot time with
ACPI enabled and '-machine gic-version=4'.

While at it, let's convert the remaining hard coded gic_version into
enumeration VIRT_GIC_VERSION_2 for consistency.

Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
Message-id: 20220812022018.1069-1-yuzenghui@huawei.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>