powerpc/dts: fix sRIO error interrupt for b4860

For B4 platform, MPIC EISR register is in reversed bitmap order,
instead of "Error interrupt source 0-31. Bit 0 represents SRC0."
the correct ordering is "Error interrupt source 0-31. Bit 0
represents SRC31." This patch is to fix sRIO EISR bit value
of error interrupt in dts node.
Signed-off-by: NMinghuan Lian <Minghuan.Lian@freescale.com>
Signed-off-by: NScott Wood <scottwood@freescale.com>

arch/powerpc/boot/dts/fsl/b4860si-post.dtsi

@@ -41,7 +41,7 @@
 
 &rio {
 	compatible = "fsl,srio";
-	interrupts = <16 2 1 11>;
+	interrupts = <16 2 1 20>;
 	#address-cells = <2>;
 	#size-cells = <2>;
 	fsl,iommu-parent = <&pamu0>;