powerpc: Add a vga alias node for P1022

In u-boot, when set the video as console, the name 'vga' is used
as a general name for the video device, during the fdt_fixup_stdout
process, the 'vga' name is used to search in the dtb to setup the
'linux,stdout-path' node. Though the P1022 DIU is not VGA-compatible
device, to meet the 'vga' name used in u-boot, the vga alias node is
added for P1022 in this patch. At the same time, a display alias is
also added so that no other components grow dependencies on the vga
alias node.
Signed-off-by: Jason Jin <Jason.Jin@freescale.com>
Signed-off-by: Wang Dongsheng <dongsheng.wang@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>

arch/powerpc/boot/dts/fsl/p1022si-post.dtsi

@@ -175,7 +175,7 @@ dma01: dma-channel@80 {
 
 /include/ "pq3-gpio-0.dtsi"
 
-	display@10000 {
+	display: display@10000 {
 		compatible = "fsl,diu", "fsl,p1022-diu";
 		reg = <0x10000 1000>;
 		interrupts = <64 2 0 0>;

arch/powerpc/boot/dts/fsl/p1022si-pre.dtsi

@@ -50,6 +50,8 @@ aliases {
 		pci0 = &pci0;
 		pci1 = &pci1;
 		pci2 = &pci2;
+		vga = &display;
+		display = &display;
 	};
 
 	cpus {