[RFC] Refactored interrupt handling on ARM

[Jakub Klama]

 On Mon, 14 Apr 2014 15:00:10 -0700, Nathan Whitehorn wrote:
> I had deliberately made it private with the last round of interrupt
> changes. The idea was to rely completely on newbus for interrupt
> mapping. Having a public interface allows code to bypass the bus
> hierarchy, which usually isn't a good thing. This ended up happening
> all over the place on PowerPC, for example. This made a lot of 
> drivers
> less MI than they should have been and took a lot of time to get rid
> of.

 Agree. In fact, we can completely remove FDT_MAP_IRQ macro, as well as
 FDT_INTR_MAX.

 Jakub