Remove unused array 'last_frame_seg_map_copy'.

This array was allocated and used to save and restore segmentation map,
however the original segmentation map was never modified between the
calls to save and restore.

Change-Id: Iaf0fbfed733c097e84cf44d2aa6b8f35d2fb456b

av1/encoder/encoder.c

diff --git a/av1/encoder/encoder.c b/av1/encoder/encoder.c
index 83a45f4..c019b71 100644
--- a/av1/encoder/encoder.c
+++ b/av1/encoder/encoder.c
@@ -375,8 +375,6 @@
   // Delete sementation map
   aom_free(cpi->segmentation_map);
   cpi->segmentation_map = NULL;
-  aom_free(cpi->coding_context.last_frame_seg_map_copy);
-  cpi->coding_context.last_frame_seg_map_copy = NULL;
 
 #if CONFIG_REF_MV
   for (i = 0; i < NMV_CONTEXTS; ++i) {
@@ -484,9 +482,6 @@
   av1_copy(cc->segment_pred_probs, cm->segp.pred_probs);
 #endif
 
-  memcpy(cpi->coding_context.last_frame_seg_map_copy, cm->last_frame_seg_map,
-         (cm->mi_rows * cm->mi_cols));
-
   av1_copy(cc->last_ref_lf_deltas, cm->lf.last_ref_deltas);
   av1_copy(cc->last_mode_lf_deltas, cm->lf.last_mode_deltas);
 
@@ -529,9 +524,6 @@
   av1_copy(cm->segp.pred_probs, cc->segment_pred_probs);
 #endif
 
-  memcpy(cm->last_frame_seg_map, cpi->coding_context.last_frame_seg_map_copy,
-         (cm->mi_rows * cm->mi_cols));
-
   av1_copy(cm->lf.last_ref_deltas, cc->last_ref_lf_deltas);
   av1_copy(cm->lf.last_mode_deltas, cc->last_mode_lf_deltas);
 
@@ -1471,12 +1463,6 @@
   aom_free(cpi->active_map.map);
   CHECK_MEM_ERROR(cm, cpi->active_map.map,
                   aom_calloc(cm->mi_rows * cm->mi_cols, 1));
-
-  // And a place holder structure is the coding context
-  // for use if we want to save and restore it
-  aom_free(cpi->coding_context.last_frame_seg_map_copy);
-  CHECK_MEM_ERROR(cm, cpi->coding_context.last_frame_seg_map_copy,
-                  aom_calloc(cm->mi_rows * cm->mi_cols, 1));
 }
 
 void av1_change_config(struct AV1_COMP *cpi, const AV1EncoderConfig *oxcf) {

av1/encoder/encoder.h

diff --git a/av1/encoder/encoder.h b/av1/encoder/encoder.h
index b7f42d0..b418ac7 100644
--- a/av1/encoder/encoder.h
+++ b/av1/encoder/encoder.h
@@ -70,8 +70,6 @@
   aom_prob segment_pred_probs[PREDICTION_PROBS];
 #endif
 
-  unsigned char *last_frame_seg_map_copy;
-
   // 0 = Intra, Last, GF, ARF
   signed char last_ref_lf_deltas[MAX_REF_FRAMES];
   // 0 = ZERO_MV, MV