irqchip/gic-v3-its: Count additional LPIs for the aliased devices

When configuring the interrupt mapping for a new device, we
iterate over all the possible aliases to account for their
maximum MSI allocation. This was introduced by e8137f4f


("irqchip: gicv3-its: Iterate over PCI aliases to generate ITS configuration").

Turns out that the code doing that is a bit braindead, and repeatedly
accounts for the same device over and over.

Fix this by counting the actual alias that is passed to us by the
core code.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Alex Shi <alex.shi@linaro.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: David Daney <ddaney.cavm@gmail.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Link: http://lkml.kernel.org/r/1443800646-8074-3-git-send-email-marc.zyngier@arm.com


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>