net/smc: add missing error check in smc_clc_prfx_set()

Coverity stumbled over a missing error check in smc_clc_prfx_set():

*** CID 1475954:  Error handling issues  (CHECKED_RETURN)
/net/smc/smc_clc.c: 233 in smc_clc_prfx_set()
>>>     CID 1475954:  Error handling issues  (CHECKED_RETURN)
>>>     Calling "kernel_getsockname" without checking return value (as is done elsewhere 8 out of 10 times).
233     	kernel_getsockname(clcsock, (struct sockaddr *)&addrs);

Add the return code check in smc_clc_prfx_set().

Fixes: c246d942ea ("net/smc: restructure netinfo for CLC proposal msgs")
Reported-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc/smc_clc.c

@@ -230,7 +230,8 @@ static int smc_clc_prfx_set(struct socket *clcsock,
 		goto out_rel;
 	}
 	/* get address to which the internal TCP socket is bound */
-	kernel_getsockname(clcsock, (struct sockaddr *)&addrs);
+	if (kernel_getsockname(clcsock, (struct sockaddr *)&addrs) < 0)
+		goto out_rel;
 	/* analyze IP specific data of net_device belonging to TCP socket */
 	addr6 = (struct sockaddr_in6 *)&addrs;
 	rcu_read_lock();