imx: ventana: added cputype env var

There are many similarities between the IMX6QUAD/IMX6DUAL and there are
many similarities between the IMX6SOLO/IMX6DUALITE. Add a 'soctype' env
variable that tells you which type you have.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>

board/gateworks/gw_ventana/gw_ventana.c

@@ -1348,6 +1348,7 @@ int misc_init_r(void)
 		else if (is_cpu_type(MXC_CPU_MX6DL) ||
 			 is_cpu_type(MXC_CPU_MX6SOLO))
 			cputype = "imx6dl";
+		setenv("soctype", cputype);
 		if (8 << (ventana_info.nand_flash_size-1) >= 2048)
 			setenv("flash_layout", "large");
 		else