vp9-denoiser: Fix to reset frame_stats.

zeromv_lastref_sse was not reset.

Change-Id: I23c12e804d63dc7dc18514f6efe71de1d1acbd6a

vp9/encoder/vp9_denoiser.c

@@ -458,6 +458,7 @@ void vp9_denoiser_update_frame_info(VP9_DENOISER *denoiser,
 void vp9_denoiser_reset_frame_stats(PICK_MODE_CONTEXT *ctx) {
   ctx->zeromv_sse = UINT_MAX;
   ctx->newmv_sse = UINT_MAX;
+  ctx->zeromv_lastref_sse = UINT_MAX;
 }
 
 void vp9_denoiser_update_frame_stats(MB_MODE_INFO *mbmi, unsigned int sse,