[RFC] Refactored interrupt handling on ARM

[Jakub Klama]

 On Mon, 14 Apr 2014 09:39:36 -0700, Nathan Whitehorn wrote:
> This is really nice! One quick question: why have you made
> FDT_MAP_IRQ() a public interface? Shouldn't calling the function it
> maps to just be a private implementation detail in nexus?
> -Nathan

 Well, FDT_MAP_IRQ() existed before my changes and was public. It just
 returned pin and discarded the node parameter:

 #define	FDT_MAP_IRQ(node, pin)	(pin)

 so I left it as is and changed the implementation to route IRQ to
 parent IC.

 Jakub