Tc decap bpf for TPR decap stats

Summary:
Based on the discussion on D49706202, moving the TPR validation stats logic to a separate tc bpf program, that will be managed outside of tw (similar to decap_info).
This diffs starts with empty prog that builds. TPR validation to be added in next diffs

Reviewed By: lalitg845

Differential Revision: D50090569

fbshipit-source-id: 9c5aa15576f4f3517c1086f5ce9b3081d2c22b51

katran/decap/tc_bpf/tc_decap_stats.bpf.c

@@ -0,0 +1,28 @@
+
+/* Copyright (C) 2019-present, Facebook, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <linux/bpf.h>
+#include <linux/pkt_cls.h>
+
+#include "katran/lib/linux_includes/bpf_helpers.h"
+
+SEC("tc")
+int tcdecapinfo(struct __sk_buff* skb) {
+  return TC_ACT_UNSPEC;
+}
+
+char _license[] SEC("license") = "GPL";