sctp: Remove extern from function prototypes

There are a mix of function prototypes with and without extern
in the kernel sources.  Standardize on not using extern for
function prototypes.

Function prototypes don't need to be written with extern.
extern is assumed by the compiler.  Its use is as unnecessary as
using auto to declare automatic/local variables in a block.
Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/sctp/sctp.h

@@ -90,12 +90,11 @@
 /*
  * sctp/protocol.c
  */
-extern int sctp_copy_local_addr_list(struct net *, struct sctp_bind_addr *,
-				     sctp_scope_t, gfp_t gfp,
-				     int flags);
-extern struct sctp_pf *sctp_get_pf_specific(sa_family_t family);
-extern int sctp_register_pf(struct sctp_pf *, sa_family_t);
-extern void sctp_addr_wq_mgmt(struct net *, struct sctp_sockaddr_entry *, int);
+int sctp_copy_local_addr_list(struct net *, struct sctp_bind_addr *,
+			      sctp_scope_t, gfp_t gfp, int flags);
+struct sctp_pf *sctp_get_pf_specific(sa_family_t family);
+int sctp_register_pf(struct sctp_pf *, sa_family_t);
+void sctp_addr_wq_mgmt(struct net *, struct sctp_sockaddr_entry *, int);
 
 /*
  * sctp/socket.c
@@ -110,7 +109,7 @@ void sctp_sock_rfree(struct sk_buff *skb);
 void sctp_copy_sock(struct sock *newsk, struct sock *sk,
 		    struct sctp_association *asoc);
 extern struct percpu_counter sctp_sockets_allocated;
-extern int sctp_asconf_mgmt(struct sctp_sock *, struct sctp_sockaddr_entry *);
+int sctp_asconf_mgmt(struct sctp_sock *, struct sctp_sockaddr_entry *);
 
 /*
  * sctp/primitive.c