s/INTERP_FILTER/InterpFilter/

this matches style guidelines and stabilizes successive runs of
clang-format across the tree. remaining types should be address in
successive commits.

Change-Id: I6ad3f69cf0a22cb9a9b895b272195f891f71170f

av1/encoder/context_tree.h

@@ -58,7 +58,7 @@ typedef struct {
   // motion vector cache for adaptive motion search control in partition
   // search loop
   MV pred_mv[TOTAL_REFS_PER_FRAME];
-  INTERP_FILTER pred_interp_filter;
+  InterpFilter pred_interp_filter;
 #if CONFIG_EXT_PARTITION_TYPES
   PARTITION_TYPE partition;
 #endif