Hello all,

Fallowing a Benjamin Herrenschmidt request, I sending you a fix for IRQ 
assign for some PCIe devices. This bug affects multiple PCIe devices 
including Cadet-E, Squib-E, CISCO 4X SDR IB, and Knox adapters.

The problem lays in the fact OF does not create an "interrupt" property 
for some PCIe device (for instance 
"pci\@800000020000204/pci1014\,0339\@0/", an IBM Raid Controller) and 
the kernel code fails returning a IRQ 0 (invalid one) if this property 
is not present.

This patch changes the way to map interrupts to if the code can not get 
"interrupts" property from PCI OF node, it falls back to standard OF 
parsing. I verified and it worked fine with a pair of Squib-E SAS 
adapter on a P6-570.