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>

arch/alpha/kernel/sys_nautilus.c

@@ -245,6 +245,10 @@ nautilus_init_pci(void)
 		IRONGATE0->pci_mem = pci_mem;
 
 	pci_bus_assign_resources(bus);
+
+	/* pci_common_swizzle() relies on bus->self being NULL
+	   for the root bus, so just clear it. */
+	bus->self = NULL;
 	pci_fixup_irqs(alpha_mv.pci_swizzle, alpha_mv.pci_map_irq);
 }