Resolve a static warning.

Change-Id: I2d481958048c4621f8c2c4866e4ab0ae69ef0403

av1/encoder/partition_search.c

diff --git a/av1/encoder/partition_search.c b/av1/encoder/partition_search.c
index 54d92be..7ca6495 100644
--- a/av1/encoder/partition_search.c
+++ b/av1/encoder/partition_search.c
@@ -789,6 +789,7 @@
   const int num_planes = av1_num_planes(cm);
   MACROBLOCKD *const xd = &x->e_mbd;
   int plane_type = (xd->tree_type == CHROMA_PART);
+  assert(bsize < BLOCK_SIZES_ALL);
   assert(IMPLIES(xd->tree_type == CHROMA_PART,
                  AOMMIN(block_size_wide[bsize], block_size_high[bsize]) > 4));
 #endif