powerpc/fsl-pci: Add PCI controller ATMU PM support

Power supply for PCI controller ATMU registers is off when system go to
deep-sleep state. So ATMU registers should be re-setup during PCI
controllers resume from sleep.

Signed-off-by: Jia Hongtao <B38951@freescale.com>
Signed-off-by: Li Yang <leoli@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>