alpha: nautilus - fix hang on boot

Recently introduced generic pci_common_swizzle() relies on bus->self
being NULL for the root PCI bus. But on nautilus bus->self points to
the host bridge device, which is necessary as we do a root bus sizing
on this system. As a result, pci_common_swizzle() loops infinitely.
This worked until 2.6.29-rc1 because the alpha-specific swizzle routine
checked for bus->parent == NULL (instead of bus->self).

Fixed by clearing bus->self after bus sizing is done.

Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Richard Henderson <rth@twiddle.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>