Reduce TPL stage QP in constant quality mode

The QP used in TPL stage is reduced for
constant quality mode.

BD-Rate performance results are as follows:

     Encoder Instruction         BD-Rate Loss(%)
cpu  Count Reduction(%)  avg.psnr  ovr.psnr  ssim     vmaf   vmaf_neg
 0         0.3           -0.2537   -0.3421   0.0421  -1.3732  -1.2476
 1        -0.9           -0.2891   -0.3724  -0.1214  -1.3278  -1.2333
 2        -0.2           -0.1307   -0.1972  -0.0926  -0.9086  -0.8639
 3        -0.2           -0.1346   -0.1869  -0.1682  -0.8484  -0.8638

STATS_CHANGED for AOM_Q mode

Change-Id: If7cfb5569f6fadde66e08d68faa26d6a1ffc4698

av1/encoder/tpl_model.c

diff --git a/av1/encoder/tpl_model.c b/av1/encoder/tpl_model.c
index ba54d55..a22341b 100644
--- a/av1/encoder/tpl_model.c
+++ b/av1/encoder/tpl_model.c
@@ -1724,7 +1724,7 @@
     if (frame_update_type == LF_UPDATE) {
       *pframe_qindex = gf_group->q_val[gf_index];
       leaf_frame_qindex = *pframe_qindex;
-      if (cpi->oxcf.rc_cfg.mode == AOM_VBR) {
+      if (cpi->oxcf.rc_cfg.mode == AOM_VBR || cpi->oxcf.rc_cfg.mode == AOM_Q) {
         const int bit_depth = cm->seq_params->bit_depth;
         const double q_val = av1_convert_qindex_to_q(*pframe_qindex, bit_depth);
         const double qindex_ratio = (double)(*pframe_qindex) / MAXQ;