Fix variable shadowing.

Change-Id: I287c61ad4aa85654aef3c871a62131bcd0d891ac

vp9/vp9_dx_iface.c

diff --git a/vp9/vp9_dx_iface.c b/vp9/vp9_dx_iface.c
index 3e21068..9e4c1a5 100644
--- a/vp9/vp9_dx_iface.c
+++ b/vp9/vp9_dx_iface.c
@@ -500,7 +500,6 @@
 
     check_resync(ctx, frame_worker_data->pbi);
   } else {
-    const VP9WorkerInterface *const winterface = vp9_get_worker_interface();
     VP9Worker *const worker = &ctx->frame_workers[ctx->next_submit_worker_id];
     FrameWorkerData *const frame_worker_data = (FrameWorkerData *)worker->data1;
     // Copy context from last worker thread to next worker thread.