net: add missing "netmap" to host_net_devices[]

Although hmp-commands.hx lists "netmap" as a valid host_net_add type,
the command rejects it because it's missing from the list.
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Message-id: 1432743412-15943-2-git-send-email-stefanha@redhat.com

net/net.c

@@ -60,6 +60,9 @@ const char *host_net_devices[] = {
 #ifdef CONFIG_NET_BRIDGE
     "bridge",
 #endif
+#ifdef CONFIG_NETMAP
+    "netmap",
+#endif
 #ifdef CONFIG_SLIRP
     "user",
 #endif