Cherry pick denoising fix

source/libvpx/vp9/encoder/vp9_denoiser.c

 /*
  *  Copyright (c) 2012 The WebM project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 460 matching lines @@
   return 0;
 }
 
 void vp9_denoiser_free(VP9_DENOISER *denoiser) {
   int i;
   denoiser->frame_buffer_initialized = 0;
   if (denoiser == NULL) {
     return;
   }
   for (i = 0; i < MAX_REF_FRAMES; ++i) {
-    if (&denoiser->running_avg_y[i] != NULL) {
-      vp9_free_frame_buffer(&denoiser->running_avg_y[i]);
-    }
+    vp9_free_frame_buffer(&denoiser->running_avg_y[i]);
   }
-  if (&denoiser->mc_running_avg_y != NULL) {
-    vp9_free_frame_buffer(&denoiser->mc_running_avg_y);
-  }
+  vp9_free_frame_buffer(&denoiser->mc_running_avg_y);
 }
 
 #ifdef OUTPUT_YUV_DENOISED
 static void make_grayscale(YV12_BUFFER_CONFIG *yuv) {
   int r, c;
   uint8_t *u = yuv->u_buffer;
   uint8_t *v = yuv->v_buffer;
 
   for (r = 0; r < yuv->uv_height; ++r) {
     for (c = 0; c < yuv->uv_width; ++c) {
       u[c] = UINT8_MAX / 2;
       v[c] = UINT8_MAX / 2;
     }
     u += yuv->uv_stride;
     v += yuv->uv_stride;
   }
 }
 #endif