Fixing broken compile for ML partition pruning

Because ML partition intra pruning is disabled by default it is not automatically checked in presubmit, hence it was broken by one of the latest merges.

Fixes #401
diff --git a/av1/encoder/partition_search.c b/av1/encoder/partition_search.c
index 6b00d18..f18a72b 100644
--- a/av1/encoder/partition_search.c
+++ b/av1/encoder/partition_search.c
@@ -6979,13 +6979,21 @@
 
   // Encoder RDO for luma component in intra region
   xd->tree_type = LUMA_PART;
+#if CONFIG_ML_PART_SPLIT
+  int force_prune_flags[3] = { 0, 0, 0 };
+#endif  // CONFIG_ML_PART_SPLIT
   if (!av1_rd_pick_partition(cpi, td, tile_data, tp, mi_row, mi_col, bsize,
 #if CONFIG_EXTENDED_SDP
                              parent_partition,
 #endif  // CONFIG_EXTENDED_SDP
                              &this_rdc, best_remain_rdcost, pc_tree, ptree_luma,
                              template_tree, max_recursion_depth, NULL, NULL,
-                             multi_pass_mode, NULL)) {
+                             multi_pass_mode, NULL
+#if CONFIG_ML_PART_SPLIT
+                             ,
+                             force_prune_flags
+#endif  // CONFIG_ML_PART_SPLIT
+                             )) {
     av1_invalid_rd_stats(&this_rdc);
     av1_invalid_rd_stats(sum_rdc);
   }
@@ -7003,7 +7011,12 @@
 #endif  // CONFIG_EXTENDED_SDP
                                &this_rdc, best_remain_rdcost, pc_tree,
                                ptree_luma, template_tree, max_recursion_depth,
-                               NULL, NULL, multi_pass_mode, NULL)) {
+                               NULL, NULL, multi_pass_mode, NULL
+#if CONFIG_ML_PART_SPLIT
+                               ,
+                               force_prune_flags
+#endif  // CONFIG_ML_PART_SPLIT
+                               )) {
       av1_invalid_rd_stats(&this_rdc);
       av1_invalid_rd_stats(sum_rdc);
     }