Fix an IOC

Change-Id: I0ca6746696d81657c035b0f6523c9af370da3c95
diff --git a/vp9/encoder/vp9_rdopt.c b/vp9/encoder/vp9_rdopt.c
index 9413d46..e7b0827 100644
--- a/vp9/encoder/vp9_rdopt.c
+++ b/vp9/encoder/vp9_rdopt.c
@@ -2585,7 +2585,7 @@
   int mode_skip_start = cpi->sf.mode_skip_start + 1;
   const int *const rd_threshes = rd_opt->threshes[segment_id][bsize];
   const int *const rd_thresh_freq_fact = rd_opt->thresh_freq_fact[bsize];
-  int mode_threshold[MAX_MODES];
+  int64_t mode_threshold[MAX_MODES];
   int *mode_map = rd_opt->mode_map[bsize];
   const int mode_search_skip_flags = cpi->sf.mode_search_skip_flags;
   vp9_zero(best_mbmode);