irqchip/gic-v3-its: Restore quirk probing for ACPI-based systems

While refactoring the way the ITSs are probed, the handling of quirks
applicable to ACPI-based platforms was lost. As a result, systems such as
HIP07 lose their GICv4 functionnality, and some other may even fail to
boot, unless they are configured to boot with DT.

Move the enabling of quirks into its_probe_one(), making it common to all
firmware implementations.

Fixes: 9585a495 ("irqchip/gic-v3-its: Split allocation from initialisation of its_node")
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240213101206.2137483-3-maz@kernel.org