irqchip: gicv3-its: Fix domain free in multi-MSI case

Fix stupid thinko on the path freeing the interrupts, where only
the first interrupt would get reset, and none of the others.

This should only affect multi-MSI allocations.

Reported-by: Wuyun Wu (Abel) <wuyun.wu@huawei.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Robert Richter <robert.richter@caviumnetworks.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>