Cherry pick denoising fix

source/libvpx/vp9/encoder/vp9_denoiser.c

Index: source/libvpx/vp9/encoder/vp9_denoiser.c
diff --git a/source/libvpx/vp9/encoder/vp9_denoiser.c b/source/libvpx/vp9/encoder/vp9_denoiser.c
index a7aaff0cfe6c2ba73c4a0e41a183fb7686928837..7d4e26aaf2f72acab9b790fd517b2cdf64e7b0e3 100644
--- a/source/libvpx/vp9/encoder/vp9_denoiser.c
+++ b/source/libvpx/vp9/encoder/vp9_denoiser.c
@@ -478,13 +478,9 @@ void vp9_denoiser_free(VP9_DENOISER *denoiser) {
     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]);
-    }
-  }
-  if (&denoiser->mc_running_avg_y != NULL) {
-    vp9_free_frame_buffer(&denoiser->mc_running_avg_y);
+    vp9_free_frame_buffer(&denoiser->running_avg_y[i]);
   }
+  vp9_free_frame_buffer(&denoiser->mc_running_avg_y);
 }
 
 #ifdef OUTPUT_YUV_DENOISED