Comment fix

This change is suggested by James Zern.

Change-Id: I4aaf00019b26a2d843775e01d124104102293cf8
diff --git a/av1/encoder/partition_search.c b/av1/encoder/partition_search.c
index 80aae1b..b54fb39 100644
--- a/av1/encoder/partition_search.c
+++ b/av1/encoder/partition_search.c
@@ -2368,7 +2368,7 @@
   this_mi[0]->partition = PARTITION_NONE;
   this_mi[0]->skip_txfm = 1;
 
-  // TODO(yunqing): functions called below can be optimized with
+  // TODO(yunqing): functions called below can be optimized by
   // removing unrelated operations.
   av1_set_offsets_without_segment_id(cpi, &tile_data->tile_info, x, mi_row,
                                      mi_col, bsize);