irqchip/gic-v5: Fix loop in gicv5_its_create_itt_two_level() cleanup path

The "i" variable in gicv5_its_create_itt_two_level() needs to be signed
otherwise it can cause a forever loop in the function's cleanup path.

[ lpieralisi: Reworded commit message ]

Fixes: 57d72196 ("irqchip/gic-v5: Add GICv5 ITS support")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Link: https://lore.kernel.org/all/20250908082745.113718-3-lpieralisi@kernel.org