hw/arm/xlnx-versal: add the target field in IRQ descriptor

hw/arm/xlnx-versal: add the target field in IRQ descriptor

Add the target field in the IRQ descriptor. This allows to target an IRQ
to another IRQ controller than the GIC(s). Other supported targets are
the PMC PPU1 CPU interrupt controller and the EAM (Error management)
device. Those two devices are currently not implemented so IRQs
targeting those will be left unconnected. This is in preparation for
versal2.

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: 20250926070806.292065-39-luc.michel@amd.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>