Remove a redundant set_flip_cfg() call.

An extra set_flip_cfg() call was added to av1_get_inv_txfm_cfg() in
commit 0c7b8d844d1226432768e08a6d9c70df4ccb58e4:
https://aomedia-review.googlesource.com/c/aom/+/43342

Change-Id: I966607285fe209ef0319646ad23ecc16b08cdae5
diff --git a/av1/common/av1_inv_txfm2d.c b/av1/common/av1_inv_txfm2d.c
index 4e69443..4f2d57b 100644
--- a/av1/common/av1_inv_txfm2d.c
+++ b/av1/common/av1_inv_txfm2d.c
@@ -183,7 +183,6 @@
                           TXFM_2D_FLIP_CFG *cfg) {
   assert(cfg != NULL);
   cfg->tx_size = tx_size;
-  set_flip_cfg(tx_type, cfg);
   av1_zero(cfg->stage_range_col);
   av1_zero(cfg->stage_range_row);
   set_flip_cfg(tx_type, cfg);