We duplicated the code in pci_alloc_pci_controller twice and had an ifdef for
iseries as well, just to select between kmalloc and bootmem memory.  Change
this so we instead pass the allocation into a common function -
pci_setup_pci_controller.

Also use a spinlock around the host_list and global_phb_number code since we
now can modify it at runtime via hotplug.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>