ARM: dts: imx6sx: Fix memory node duplication

Boards based on imx6sx have duplicate memory nodes:

- One coming from the board dts file: memory@

- One coming from the imx6sx.dtsi file.

Fix the duplication by removing the memory node from the dtsi file
and by adding 'device_type = "memory";' in the board dts.
Reported-by: Rob Herring <robh@kernel.org>
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx6sx-nitrogen6sx.dts

@@ -12,6 +12,7 @@ / {
 	compatible = "boundary,imx6sx-nitrogen6sx", "fsl,imx6sx";
 
 	memory@80000000 {
+		device_type = "memory";
 		reg = <0x80000000 0x40000000>;
 	};
 

arch/arm/boot/dts/imx6sx-sabreauto.dts

@@ -11,6 +11,7 @@ / {
 	compatible = "fsl,imx6sx-sabreauto", "fsl,imx6sx";
 
 	memory@80000000 {
+		device_type = "memory";
 		reg = <0x80000000 0x80000000>;
 	};
 

arch/arm/boot/dts/imx6sx-sdb.dtsi

@@ -21,6 +21,7 @@ chosen {
 	};
 
 	memory@80000000 {
+		device_type = "memory";
 		reg = <0x80000000 0x40000000>;
 	};
 

arch/arm/boot/dts/imx6sx-softing-vining-2000.dts

@@ -21,6 +21,7 @@ chosen {
 	};
 
 	memory@80000000 {
+		device_type = "memory";
 		reg = <0x80000000 0x40000000>;
 	};
 

arch/arm/boot/dts/imx6sx-udoo-neo-basic.dts

@@ -49,6 +49,7 @@ / {
 	compatible = "udoo,neobasic", "fsl,imx6sx";
 
 	memory@80000000 {
+		device_type = "memory";
 		reg = <0x80000000 0x20000000>;
 	};
 };

arch/arm/boot/dts/imx6sx-udoo-neo-extended.dts

@@ -49,6 +49,7 @@ / {
 	compatible = "udoo,neoextended", "fsl,imx6sx";
 
 	memory@80000000 {
+		device_type = "memory";
 		reg = <0x80000000 0x40000000>;
 	};
 };

arch/arm/boot/dts/imx6sx-udoo-neo-full.dts

@@ -49,6 +49,7 @@ / {
 	compatible = "udoo,neofull", "fsl,imx6sx";
 
 	memory@80000000 {
+		device_type = "memory";
 		reg = <0x80000000 0x40000000>;
 	};
 };

arch/arm/boot/dts/imx6sx.dtsi

@@ -15,10 +15,8 @@ / {
 	 * The decompressor and also some bootloaders rely on a
 	 * pre-existing /chosen node to be available to insert the
 	 * command line and merge other ATAGS info.
-	 * Also for U-Boot there must be a pre-existing /memory node.
 	 */
 	chosen {};
-	memory { device_type = "memory"; };
 
 	aliases {
 		can0 = &flexcan1;