Scale up exhaustive_search_thresh to work with 128x128 partitions

Also use int instead of int64_t since sf->exhaustive_searches_thresh is
an int and we only make it smaller.

Change-Id: I38c9ebd97f085cb7ce5094dfc98942bb2171ee0f
diff --git a/av1/encoder/mcomp.c b/av1/encoder/mcomp.c
index c6e11a5..c77a43c 100644
--- a/av1/encoder/mcomp.c
+++ b/av1/encoder/mcomp.c
@@ -2301,9 +2301,9 @@
 
       // Should we allow a follow on exhaustive search?
       if (is_exhaustive_allowed(cpi, x)) {
-        int64_t exhuastive_thr = sf->exhaustive_searches_thresh;
+        int exhuastive_thr = sf->exhaustive_searches_thresh;
         exhuastive_thr >>=
-            8 - (b_width_log2_lookup[bsize] + b_height_log2_lookup[bsize]);
+            10 - (b_width_log2_lookup[bsize] + b_height_log2_lookup[bsize]);
 
         // Threshold variance for an exhaustive full search.
         if (var > exhuastive_thr) {