powerpc/85xx: Fix setting of LIODN prop in PCIe nodes on P3041/P5020

powerpc/85xx: Fix setting of LIODN prop in PCIe nodes on P3041/P5020

We utilize the compatible string to find the node to add fsl,liodn
property to.  However P3041 & P5020 don't have "fsl,p4080-pcie"
compatible for their PCIe controllers as they aren't backwards compatible.

Allow the macro's to specify the PCIe compatible to use to allow SoC
uniqueness.  On P3041 & P5020 we utilize "fsl,qoriq-pcie-v2.2" for the
PCIe controllers.

Signed-off-by: Laurentiu TUDOR <Laurentiu.Tudor@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>