Remove av1_cost_coeffs from rdopt.h if using PVQ.

Change-Id: I08a2437e4eb2ef31ec7a675fba6bcec538019241
diff --git a/av1/encoder/rdopt.h b/av1/encoder/rdopt.h
index b586b45..dc450f6 100644
--- a/av1/encoder/rdopt.h
+++ b/av1/encoder/rdopt.h
@@ -128,11 +128,12 @@
   }
 #endif
 }
-
+#if !CONFIG_PVQ
 int av1_cost_coeffs(const AV1_COMMON *const cm, MACROBLOCK *x, int plane,
                     int block, int coeff_ctx, TX_SIZE tx_size,
                     const int16_t *scan, const int16_t *nb,
                     int use_fast_coef_costing);
+#endif
 void av1_rd_pick_intra_mode_sb(const struct AV1_COMP *cpi, struct macroblock *x,
                                struct RD_COST *rd_cost, BLOCK_SIZE bsize,
                                PICK_MODE_CONTEXT *ctx, int64_t best_rd);