fix compiler warning of unused parameters

when configured with --enable-pvq

Change-Id: I10672cf16393d79e00b74f1a58ebc609b7b2c66f

av1/encoder/rdopt.c

diff --git a/av1/encoder/rdopt.c b/av1/encoder/rdopt.c
index 9bc9dd1..2905864 100644
--- a/av1/encoder/rdopt.c
+++ b/av1/encoder/rdopt.c
@@ -1166,8 +1166,10 @@
   MB_MODE_INFO *const mbmi = &xd->mi[0]->mbmi;
   const AV1_COMMON *cm = &args->cpi->common;
   int64_t rd1, rd2, rd;
+#if !CONFIG_PVQ
   int coeff_ctx = combine_entropy_contexts(*(args->t_above + blk_col),
                                            *(args->t_left + blk_row));
+#endif
   RD_STATS this_rd_stats;
   av1_init_rd_stats(&this_rd_stats);