sctp: move SCTP_PAD4 and SCTP_TRUNC4 to linux/sctp.h

Move these two macros from net/sctp/sctp.h to linux/sctp.h, so that
it will be enough to include only linux/sctp.h in nft_exthdr.c and
xt_sctp.c. It should not include "net/sctp/sctp.h" if a module does
not have a dependence on SCTP module.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: Saeed Mahameed <saeed@kernel.org>
Link: https://lore.kernel.org/r/ef6468a687f36da06f575c2131cd4612f6b7be88.1668526821.git.lucien.xin@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

include/linux/sctp.h

@@ -820,4 +820,9 @@ struct sctp_new_encap_port_hdr {
 	__be16 new_port;
 };
 
+/* Round an int up to the next multiple of 4.  */
+#define SCTP_PAD4(s) (((s)+3)&~3)
+/* Truncate to the previous multiple of 4.  */
+#define SCTP_TRUNC4(s) ((s)&~3)
+
 #endif /* __LINUX_SCTP_H__ */

include/net/sctp/sctp.h

@@ -67,11 +67,6 @@
 #define SCTP_PROTOSW_FLAG INET_PROTOSW_PERMANENT
 #endif
 
-/* Round an int up to the next multiple of 4.  */
-#define SCTP_PAD4(s) (((s)+3)&~3)
-/* Truncate to the previous multiple of 4.  */
-#define SCTP_TRUNC4(s) ((s)&~3)
-
 /*
  * Function declarations.
  */

net/netfilter/nft_exthdr.c

@@ -13,7 +13,6 @@
 #include <linux/sctp.h>
 #include <net/netfilter/nf_tables_core.h>
 #include <net/netfilter/nf_tables.h>
-#include <net/sctp/sctp.h>
 #include <net/tcp.h>
 
 struct nft_exthdr {

net/netfilter/xt_sctp.c

@@ -4,7 +4,6 @@
 #include <linux/skbuff.h>
 #include <net/ip.h>
 #include <net/ipv6.h>
-#include <net/sctp/sctp.h>
 #include <linux/sctp.h>
 
 #include <linux/netfilter/x_tables.h>