unicore32/PCI: move <asm-generic/pci-bridge.h> include to asm/pci.h

Move this include to be consistent with other architectures.

CC: Guan Xuetao <gxt@mprc.pku.edu.cn>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>