fwd_txfm2d: switch Highway to AVX3_DL

libaom's AVX512 guarantees AVX3_DL support.

Change-Id: If3b80b27a57b39bf10301c1406e8c51665e9cc3d

av1/encoder/x86/av1_fwd_txfm2d_hwy_avx512.cc

diff --git a/av1/encoder/x86/av1_fwd_txfm2d_hwy_avx512.cc b/av1/encoder/x86/av1_fwd_txfm2d_hwy_avx512.cc
index 7bd3144..c92a3d9 100644
--- a/av1/encoder/x86/av1_fwd_txfm2d_hwy_avx512.cc
+++ b/av1/encoder/x86/av1_fwd_txfm2d_hwy_avx512.cc
@@ -9,7 +9,7 @@
  * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
  */
 
-#define HWY_BASELINE_TARGETS HWY_AVX3
+#define HWY_BASELINE_TARGETS HWY_AVX3_DL
 #define HWY_BROKEN_32BIT 0
 
 #include "av1/encoder/av1_fwd_txfm2d_hwy.h"