net/sched: Retire ipt action

The tc ipt action was intended to run all netfilter/iptables target.
Unfortunately it has not benefitted over the years from proper updates when
netfilter changes, and for that reason it has remained rudimentary.
Pinging a bunch of people that i was aware were using this indicates that
removing it wont affect them.
Retire it to reduce maintenance efforts. Buh-bye.

Reviewed-by: Victor Noguiera <victor@mojatatu.com>
Reviewed-by: Pedro Tammela <pctammela@mojatatu.com>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/pkt_cls.h

@@ -99,7 +99,7 @@ enum {
  * versions.
  */
 #define TCA_ACT_GACT 5
-#define TCA_ACT_IPT 6
+#define TCA_ACT_IPT 6 /* obsoleted, can be reused */
 #define TCA_ACT_PEDIT 7
 #define TCA_ACT_MIRRED 8
 #define TCA_ACT_NAT 9
@@ -120,7 +120,7 @@ enum tca_id {
 	TCA_ID_UNSPEC = 0,
 	TCA_ID_POLICE = 1,
 	TCA_ID_GACT = TCA_ACT_GACT,
-	TCA_ID_IPT = TCA_ACT_IPT,
+	TCA_ID_IPT = TCA_ACT_IPT, /* Obsoleted, can be reused */
 	TCA_ID_PEDIT = TCA_ACT_PEDIT,
 	TCA_ID_MIRRED = TCA_ACT_MIRRED,
 	TCA_ID_NAT = TCA_ACT_NAT,

include/uapi/linux/tc_act/tc_ipt.h

@@ -1,20 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
-#ifndef __LINUX_TC_IPT_H
-#define __LINUX_TC_IPT_H
-
-#include <linux/pkt_cls.h>
-
-enum {
-	TCA_IPT_UNSPEC,
-	TCA_IPT_TABLE,
-	TCA_IPT_HOOK,
-	TCA_IPT_INDEX,
-	TCA_IPT_CNT,
-	TCA_IPT_TM,
-	TCA_IPT_TARG,
-	TCA_IPT_PAD,
-	__TCA_IPT_MAX
-};
-#define TCA_IPT_MAX (__TCA_IPT_MAX - 1)
-                                                                                
-#endif