Cherry pick buffer re-allocation fix

source/libvpx/vp9/decoder/vp9_decoder.c

Index: source/libvpx/vp9/decoder/vp9_decoder.c
diff --git a/source/libvpx/vp9/decoder/vp9_decoder.c b/source/libvpx/vp9/decoder/vp9_decoder.c
index 288d8690ca244fb2c9ded53f629e83af974d66ae..cf1f23fb98f193dfe2abd0e10a97381fdc0aa0db 100644
--- a/source/libvpx/vp9/decoder/vp9_decoder.c
+++ b/source/libvpx/vp9/decoder/vp9_decoder.c
@@ -50,7 +50,6 @@ static void initialize_dec(void) {
 
 static void vp9_dec_setup_mi(VP9_COMMON *cm) {
   cm->mi = cm->mip + cm->mi_stride + 1;
-  memset(cm->mip, 0, cm->mi_stride * (cm->mi_rows + 1) * sizeof(*cm->mip));
   cm->mi_grid_visible = cm->mi_grid_base + cm->mi_stride + 1;
   memset(cm->mi_grid_base, 0,
          cm->mi_stride * (cm->mi_rows + 1) * sizeof(*cm->mi_grid_base));