FreeBSD/armv6 in QEMU

[Oleksandr Tymoshenko]

Hello,

I fixed several bugs in versatilepb support for FreeBSD but there
is one change in QEMU that requires users' attention. Apparently
PCI IRQ routing logic in VersatilePB QEMU emulation was not the
same as real harwdare's. They fixed it in QEMU 1.5 and added the
way to fall back to previous behaviour. So we could either fix logic
and break all pre-1.5 QEMU versions or keep old logic and
run on older version out of the box and on 1.5 with some
additional configuration. After some thoughts I decided to go
with latter. So if you use QEMU 1.5 just add this option to
command line:
    -global versatile_pci.broken-irq-mapping=1

Previous version should just work with latest HEAD (I tested QEMU 1.3)