Initialize wifi_set_nodfs_flag with a stub

It is not implmented on some platforms.

Bug: 20841930
Change-Id: Iba167eadb430b532102060603b30297a3b7a98cb
diff --git a/service/jni/com_android_server_wifi_WifiNative.cpp b/service/jni/com_android_server_wifi_WifiNative.cpp
index 4ad82ed..a97ec05 100644
--- a/service/jni/com_android_server_wifi_WifiNative.cpp
+++ b/service/jni/com_android_server_wifi_WifiNative.cpp
@@ -78,6 +78,7 @@
     hal_fn->wifi_disable_tdls = wifi_disable_tdls_stub;
     hal_fn->wifi_get_tdls_status = wifi_get_tdls_status_stub;
     hal_fn->wifi_get_tdls_capabilities = wifi_get_tdls_capabilities_stub;
+    hal_fn->wifi_set_nodfs_flag = wifi_set_nodfs_flag_stub;
     return 0;
 }