ARM: dts: vf: Fix memory node duplication

Boards based on vf500/vf600 have duplicate memory nodes:

- One coming from the board dts file: memory@

- One coming from the vf500.dtsi/vf610m4.dtsi files.

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 <[e-mail]>
Signed-off-by: Fabio Estevam <[e-mail]>
Reviewed-by: Stefan Agner <[e-mail]>
Signed-off-by: Shawn Guo <[e-mail]>

arch/arm/boot/dts/vf500-colibri.dtsi

···
 	compatible = "toradex,vf610-colibri_vf50", "fsl,vf500";
 
 	memory@80000000 {
+		device_type = "memory";
 		reg = <0x80000000 0x8000000>;
 	};
 

arch/arm/boot/dts/vf500.dtsi

···
 	#size-cells = <1>;
 	chosen { };
 	aliases { };
-	memory { device_type = "memory"; };
 
 	cpus {
 		#address-cells = <1>;

arch/arm/boot/dts/vf610-bk4.dts

···
 	};
 
 	memory@80000000 {
+		device_type = "memory";
 		reg = <0x80000000 0x8000000>;
 	};
 

arch/arm/boot/dts/vf610-colibri.dtsi

···
 	compatible = "toradex,vf610-colibri_vf61", "fsl,vf610";
 
 	memory@80000000 {
+		device_type = "memory";
 		reg = <0x80000000 0x10000000>;
 	};
 };

arch/arm/boot/dts/vf610-cosmic.dts

···
 	};
 
 	memory@80000000 {
+		device_type = "memory";
 		reg = <0x80000000 0x10000000>;
 	};
 

arch/arm/boot/dts/vf610-twr.dts

···
 	};
 
 	memory@80000000 {
+		device_type = "memory";
 		reg = <0x80000000 0x8000000>;
 	};
 

arch/arm/boot/dts/vf610-zii-cfu1.dts

···
 	};
 
 	memory@80000000 {
+		device_type = "memory";
 		reg = <0x80000000 0x20000000>;
 	};
 

arch/arm/boot/dts/vf610-zii-dev.dtsi

···
 	};
 
 	memory@80000000 {
+		device_type = "memory";
 		reg = <0x80000000 0x20000000>;
 	};
 

arch/arm/boot/dts/vf610-zii-ssmb-spu3.dts

···
 	};
 
 	memory@80000000 {
+		device_type = "memory";
 		reg = <0x80000000 0x20000000>;
 	};
 

arch/arm/boot/dts/vf610m4-colibri.dts

···
 	};
 
 	memory@8c000000 {
+		device_type = "memory";
 		reg = <0x8c000000 0x3000000>;
 	};
 };

arch/arm/boot/dts/vf610m4.dtsi

···
 	#size-cells = <1>;
 	chosen { };
 	aliases { };
-	memory { device_type = "memory"; };
 };
 
 &mscm_ir {