powerpc/mpc5121: correct DIU compatible property

The DIU driver should bind against "fsl,mpc5121-diu"
directly. Add this compatible property to the match
table and fix DTS and platform code accordingly.

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/arch/powerpc/boot/dts/mpc5121ads.dts b/arch/powerpc/boot/dts/mpc5121ads.dts
index d2b2db7..c9ef6bb 100644
--- a/arch/powerpc/boot/dts/mpc5121ads.dts
+++ b/arch/powerpc/boot/dts/mpc5121ads.dts
@@ -255,7 +255,7 @@
 		};
 
 		display@2100 {
-			compatible = "fsl,mpc5121-diu", "fsl,diu";
+			compatible = "fsl,mpc5121-diu";
 			reg = <0x2100 0x100>;
 			interrupts = <64 0x8>;
 			interrupt-parent = < &ipic >;