km/common: enable "env default" for all keymile boards

Signed-off-by: Gerlando Falauto <gerlando.falauto@keymile.com>
Signed-off-by: Holger Brunck <holger.brunck@keymile.com>

include/configs/km/keymile-common.h

@@ -37,6 +37,7 @@
 
 #define CONFIG_CMD_ASKENV
 #define CONFIG_CMD_DHCP
+#define CONFIG_CMD_DEFAULTENV_VARS
 #define CONFIG_CMD_ECHO
 #define CONFIG_CMD_IMMAP
 #define CONFIG_CMD_MII