pci: fix section mismatch warning

drivers/pci/search.c caused following section mismatch warning
(if compiled with CONFIG_HOTPLUG=n):

WARNING: drivers/pci/built-in.o - Section mismatch: reference to .init.text: from .text.pci_find_bus after 'pci_find_bus' (at offset 0x24)

This was due to pci_find_bus() calling a function marked __devinit.
Fix was to remove the __devinit from the offending function.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>