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/mpc8560ads.dts

@@ -291,7 +291,6 @@
 	};
 
 	pci0: pci@e0008000 {
-		cell-index = <0>;
 		#interrupt-cells = <1>;
 		#size-cells = <2>;
 		#address-cells = <3>;