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: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1432743412-15943-2-git-send-email-stefanha@redhat.com
diff --git a/net/net.c b/net/net.c
index cc36c7b..f43af97 100644
--- a/net/net.c
+++ b/net/net.c
@@ -60,6 +60,9 @@
 #ifdef CONFIG_NET_BRIDGE
     "bridge",
 #endif
+#ifdef CONFIG_NETMAP
+    "netmap",
+#endif
 #ifdef CONFIG_SLIRP
     "user",
 #endif