irqchip/armada-370-xp: Use the generic MSI infrastructure

This commit moves the irq-armada-370-xp driver from using the
PCI-specific MSI infrastructure to the generic MSI infrastructure, to
which drivers are progressively converted.

In this hardware, the MSI controller is directly bundled inside the
interrupt controller, so we have a single Device Tree node to which
multiple IRQ domaines are attached: the wired interrupt domain and the
MSI interrupt domain. In order to ensure that they can be
differentiated, we have to force the bus_token of the wired interrupt
domain to be DOMAIN_BUS_WIRED. The MSI domain bus_token is
automatically set to the appropriate value by
pci_msi_create_irq_domain().

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Suggested-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Link: https://lkml.kernel.org/r/1455115621-22846-3-git-send-email-thomas.petazzoni@free-electrons.com


Signed-off-by: Jason Cooper <jason@lakedaemon.net>