ARM: 7647/1: pci: Keep pci_common_init() around after init

When using deferred driver probing, PCI host controller drivers may
actually require this function after the init stage.

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>