Remove disabling soft quantization conditioned on qm

The soft quantization supports the use of quantization matrix now.
Remove this condition in speed feature.

Change-Id: I82909a575ba8b872f3a85ea64e20157a7f186d20
diff --git a/av1/encoder/speed_features.c b/av1/encoder/speed_features.c
index ac5d62f..20386d9 100644
--- a/av1/encoder/speed_features.c
+++ b/av1/encoder/speed_features.c
@@ -911,9 +911,6 @@
   // No recode or trellis for 1 pass.
   if (oxcf->pass == 0) sf->recode_loop = DISALLOW_RECODE;
 
-  // FIXME: trellis not very efficient for quantization matrices
-  if (oxcf->using_qm) sf->optimize_coefficients = NO_TRELLIS_OPT;
-
   if (sf->mv.subpel_search_method == SUBPEL_TREE) {
     cpi->find_fractional_mv_step = av1_find_best_sub_pixel_tree;
   } else if (sf->mv.subpel_search_method == SUBPEL_TREE_PRUNED) {