Remove CONFIG_GLOBAL_MOTION_SEARCH compile flag

This flag is now redundant since we have added a command line
option to disable global motion usage.

Change-Id: I584586ce75153cd76ac54a60b9ed265a967a535a
diff --git a/av1/encoder/encodeframe.c b/av1/encoder/encodeframe.c
index b5ea46f..2247809 100644
--- a/av1/encoder/encodeframe.c
+++ b/av1/encoder/encodeframe.c
@@ -5847,9 +5847,6 @@
 
   av1_zero(rdc->global_motion_used);
   av1_zero(cpi->gmparams_cost);
-#if !CONFIG_GLOBAL_MOTION_SEARCH
-  cpi->global_motion_search_done = 1;
-#endif  // !CONFIG_GLOBAL_MOTION_SEARCH
   if (cpi->common.current_frame.frame_type == INTER_FRAME && cpi->source &&
       cpi->oxcf.enable_global_motion && !cpi->global_motion_search_done) {
     YV12_BUFFER_CONFIG *ref_buf[REF_FRAMES];
diff --git a/build/cmake/aom_config_defaults.cmake b/build/cmake/aom_config_defaults.cmake
index feb9b5e..ba4b99f 100644
--- a/build/cmake/aom_config_defaults.cmake
+++ b/build/cmake/aom_config_defaults.cmake
@@ -121,8 +121,6 @@
 set_aom_config_var(CONFIG_SPATIAL_RESAMPLING 1 NUMBER "Spatial resampling.")
 set_aom_config_var(DECODE_HEIGHT_LIMIT 0 NUMBER "Set limit for decode height.")
 set_aom_config_var(DECODE_WIDTH_LIMIT 0 NUMBER "Set limit for decode width.")
-set_aom_config_var(CONFIG_GLOBAL_MOTION_SEARCH 1 NUMBER
-                   "Global motion search flag.")
 
 # AV1 experiment flags.
 set_aom_config_var(CONFIG_COLLECT_INTER_MODE_RD_STATS 1 NUMBER