[PATCH] PCI: msi abstractions and support for altix

Abstract portions of the MSI core for platforms that do not use standard
APIC interrupt controllers.  This is implemented through a new arch-specific
msi setup routine, and a set of msi ops which can be set on a per platform
basis.

Signed-off-by: Mark Maule <maule@sgi.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>