net/smc: make smc_hash_sk/smc_unhash_sk static

smc_hash_sk and smc_unhash_sk are only used in af_smc.c, so make them
static and remove the output symbol. They can be called under the path
.prot->hash()/unhash().

Signed-off-by: Zhengchao Shao <[e-mail]>
Reviewed-by: Wen Gu <[e-mail]>
Reviewed-by: Simon Horman <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/net/smc.h

···
 	struct hlist_head ht;
 };
 
-int smc_hash_sk(struct sock *sk);
-void smc_unhash_sk(struct sock *sk);
-
 /* SMCD/ISM device driver interface */
 struct smcd_dmb {
 	u64 dmb_tok;

net/smc/af_smc.c

···
 	.lock = __RW_LOCK_UNLOCKED(smc_v6_hashinfo.lock),
 };
 
-int smc_hash_sk(struct sock *sk)
+static int smc_hash_sk(struct sock *sk)
 {
 	struct smc_hashinfo *h = sk->sk_prot->h.smc_hash;
 	struct hlist_head *head;
···
 
 	return 0;
 }
-EXPORT_SYMBOL_GPL(smc_hash_sk);
 
-void smc_unhash_sk(struct sock *sk)
+static void smc_unhash_sk(struct sock *sk)
 {
 	struct smc_hashinfo *h = sk->sk_prot->h.smc_hash;
 
···
 		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 	write_unlock_bh(&h->lock);
 }
-EXPORT_SYMBOL_GPL(smc_unhash_sk);
 
 /* This will be called before user really release sock_lock. So do the
  * work which we didn't do because of user hold the sock_lock in the