Localize a variable in get_this_mv()

Change-Id: I4bd95089ffe6669a9cdac8d7386f5095dee0e6ef
diff --git a/av1/encoder/rdopt.c b/av1/encoder/rdopt.c
index df909e3..3e9d3ae 100644
--- a/av1/encoder/rdopt.c
+++ b/av1/encoder/rdopt.c
@@ -9605,7 +9605,6 @@
                                int ref_idx, int ref_mv_idx,
                                const MV_REFERENCE_FRAME *ref_frame,
                                const MB_MODE_INFO_EXT *mbmi_ext) {
-  const uint8_t ref_frame_type = av1_ref_frame_type(ref_frame);
   const int is_comp_pred = ref_frame[1] > INTRA_FRAME;
   const PREDICTION_MODE single_mode =
       get_single_mode(this_mode, ref_idx, is_comp_pred);
@@ -9616,6 +9615,7 @@
     *this_mv = mbmi_ext->global_mvs[ref_frame[ref_idx]];
   } else {
     assert(single_mode == NEARMV || single_mode == NEARESTMV);
+    const uint8_t ref_frame_type = av1_ref_frame_type(ref_frame);
     const int ref_mv_offset = single_mode == NEARESTMV ? 0 : ref_mv_idx + 1;
     if (ref_mv_offset < mbmi_ext->ref_mv_count[ref_frame_type]) {
       assert(ref_mv_offset >= 0);