ARM: dts: imx: Pass empty memory size on board dts

In preparation for removing 'reg = <0 0>;' from the dtsi SoC files, pass
'reg = <0 0 >;' to the dts/dtsi board files that do not pass the memory
size.

Signed-off-by: Marco Franchi <marco.franchi@nxp.com>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx6dl-ts7970.dts

@@ -47,4 +47,9 @@
 / {
 	model = "Technologic Systems i.MX6 Solo/DualLite TS-7970 (Default Device Tree)";
 	compatible = "technologic,imx6dl-ts7970", "fsl,imx6dl";
+
+	/* Will be filled by the bootloader */
+	memory {
+		reg = <0 0>;
+	};
 };