ARM: use high vectors if possible

[Jean-Christophe PLAGNIOL-VILLARD]

On 08:46 Mon 08 Aug     , Sascha Hauer wrote:
> Created this series to get high vector support. Using high vectors
> at 0xffff0000 allow us to map in a faulting page at 0x0 with which
> we can catch NULL pointer dereferences. The other patches are only
> some cleanups around exceptions which I came along the way.
be careful on ixp4xx (which I work on 0x0 is the nor flash address)

Best Regards,
J.