Renamings for OBMC experiment

To get ready for pulling AV1 to nextgenv2
Replace the experimental flag by MOTION_VAR. Rename major variables.

Change-Id: If6cf4f37b9319c46d8f90df551cc7295d66ca205
diff --git a/av1/common/reconinter.h b/av1/common/reconinter.h
index 26a4590..4f86354 100644
--- a/av1/common/reconinter.h
+++ b/av1/common/reconinter.h
@@ -214,9 +214,9 @@
 #endif  // CONFIG_EXT_INTER
 
 void build_inter_predictors(MACROBLOCKD *xd, int plane,
-#if CONFIG_OBMC
+#if CONFIG_MOTION_VAR
                             int mi_col_offset, int mi_row_offset,
-#endif  // CONFIG_OBMC
+#endif  // CONFIG_MOTION_VAR
                             int block, int bw, int bh, int x, int y, int w,
                             int h,
 #if CONFIG_SUPERTX && CONFIG_EXT_INTER
@@ -515,7 +515,7 @@
 }
 #endif  // CONFIG_EXT_INTERP
 
-#if CONFIG_OBMC
+#if CONFIG_MOTION_VAR
 const uint8_t *av1_get_obmc_mask(int length);
 void av1_build_obmc_inter_prediction(AV1_COMMON *cm, MACROBLOCKD *xd,
                                      int mi_row, int mi_col,
@@ -535,7 +535,7 @@
                                         int tmp_width[MAX_MB_PLANE],
                                         int tmp_height[MAX_MB_PLANE],
                                         int tmp_stride[MAX_MB_PLANE]);
-#endif  // CONFIG_OBMC
+#endif  // CONFIG_MOTION_VAR
 
 #if CONFIG_EXT_INTER
 #define MASK_MASTER_SIZE (2 * MAX_SB_SIZE)