Clean-up auto_min_partition_based_on_simple_motion speed feature

cleaned up unused speed feature auto_min_partition_based_on_simple_motion

Change-Id: I15678a30dcc99b29a9ac46c9c93058dc95899930
diff --git a/av1/encoder/speed_features.c b/av1/encoder/speed_features.c
index 80e7482..854b710 100644
--- a/av1/encoder/speed_features.c
+++ b/av1/encoder/speed_features.c
@@ -1075,7 +1075,6 @@
   part_sf->less_rectangular_check_level = 0;
   part_sf->use_square_partition_only_threshold = BLOCK_128X128;
   part_sf->auto_max_partition_based_on_simple_motion = NOT_IN_USE;
-  part_sf->auto_min_partition_based_on_simple_motion = 0;
   part_sf->default_max_partition_size = BLOCK_LARGEST;
   part_sf->default_min_partition_size = BLOCK_4X4;
   part_sf->adjust_var_based_rd_partitioning = 0;
diff --git a/av1/encoder/speed_features.h b/av1/encoder/speed_features.h
index 6c0f6bd..a01b25f 100644
--- a/av1/encoder/speed_features.h
+++ b/av1/encoder/speed_features.h
@@ -419,11 +419,10 @@
   // Use square partition only beyond this block size.
   BLOCK_SIZE use_square_partition_only_threshold;
 
-  // Sets min and max square partition levels for this superblock based on
+  // Sets max square partition levels for this superblock based on
   // motion vector and prediction error distribution produced from 16x16
   // simple motion search
   MAX_PART_PRED_MODE auto_max_partition_based_on_simple_motion;
-  int auto_min_partition_based_on_simple_motion;
 
   // Min and max square partition size we enable (block_size) as per auto
   // min max, but also used by adjust partitioning, and pick_partitioning.