irqchip/gic-v3-its: Remove usage of the deprecated ida_simple_xx() API

ida_alloc() and ida_free() should be used instead of the deprecated
ida_simple_get() and ida_simple_remove().

The upper limit of ida_simple_get() is exclusive, but the one of
ida_alloc_max() is inclusive. Adjust the code accordingly.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/3b472b0e7edf6e483b8b255cf8d1cb0163532adf.1705222332.git.christophe.jaillet@wanadoo.fr