hw/arm/xlnx-versal: add support for multiple GICs

hw/arm/xlnx-versal: add support for multiple GICs

The Versal SoC contains two GICs: one GICv3 in the APU and one GICv2 in
the RPU (currently not instantiated). To prepare for the GICv2
instantiation, add support for multiple GICs when connecting interrupts.

When a GIC is created, the first-cpu-index property is set on it, and a
pointer to the GIC is stored in the intc array. When connecting an IRQ,
a TYPE_SPLIT_IRQ device is created with its num-lines property set to
the number of GICs in the SoC. The split device is used to fan out the
IRQ to all the GICs.

Signed-off-by: Luc Michel <luc.michel@amd.com>
Reviewed-by: Francisco Iglesias <francisco.iglesias@amd.com>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@amd.com>
Tested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20250926070806.292065-25-luc.michel@amd.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>