freedom-k64f/demo: Enable netcat app

Change-Id: I98e72d341f46c2e03efdb6cc93124a2f49613f19
Relate-to: apache#1988
Relate-to: apache/nuttx-apps#482
Relate-to: rzr/aframe-smart-home#3
Forwarded: apache#2333
Signed-off-by: Philippe Coval <rzr@users.sf.net>

boards/arm/kinetis/freedom-k64f/configs/demo/defconfig

@@ -46,6 +46,7 @@ CONFIG_MMCSD_MULTIBLOCK_DISABLE=y
 CONFIG_MMCSD_SDIO=y
 CONFIG_MOTOROLA_SREC=y
 CONFIG_NETDB_DNSCLIENT=y
+CONFIG_NETUTILS_NETCAT=y
 CONFIG_NET_BROADCAST=y
 CONFIG_NET_SOCKOPTS=y
 CONFIG_NET_TCP=y