vp9enc: remove duplicate declaration of function
diff --git a/ext/vpx/gstvp9enc.c b/ext/vpx/gstvp9enc.c
index 5b2f896..e64f5af 100644
--- a/ext/vpx/gstvp9enc.c
+++ b/ext/vpx/gstvp9enc.c
@@ -350,7 +350,6 @@
 static GstFlowReturn gst_vp9_enc_drain (GstVideoEncoder * video_encoder);
 static GstFlowReturn gst_vp9_enc_handle_frame (GstVideoEncoder *
     video_encoder, GstVideoCodecFrame * frame);
-static GstFlowReturn gst_vp9_enc_drain (GstVideoEncoder * video_encoder);
 static gboolean gst_vp9_enc_sink_event (GstVideoEncoder *
     video_encoder, GstEvent * event);
 static gboolean gst_vp9_enc_propose_allocation (GstVideoEncoder * encoder,