powerpc/fsl: Remove cell-index from PCI nodes

The cell-index property isn't used on PCI nodes and is ill defined.
Remove it for now and if someone comes up with a good reason and
consistent definition for it we can add it back

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

arch/powerpc/boot/dts/mpc8379_mds.dts

@@ -397,7 +397,6 @@
 	};
 
 	pci0: pci@e0008500 {
-		cell-index = <0>;
 		interrupt-map-mask = <0xf800 0x0 0x0 0x7>;
 		interrupt-map = <