smb3: fix uninitialized value for port in witness protocol move

Although in practice this can not occur (since IPv4 and IPv6 are the
only two cases currently supported), it is cleaner to avoid uninitialized
variable warnings.

Addresses smatch warning:
  fs/cifs/cifs_swn.c:468 cifs_swn_store_swn_addr() error: uninitialized symbol 'port'.
Reported-by: Nkernel test robot <lkp@intel.com>
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
CC: Samuel Cabrero <scabrero@suse.de>
Signed-off-by: NSteve French <stfrench@microsoft.com>

fs/cifs/cifs_swn.c

@@ -447,15 +447,13 @@ static int cifs_swn_store_swn_addr(const struct sockaddr_storage *new,
 				   const struct sockaddr_storage *old,
 				   struct sockaddr_storage *dst)
 {
-	__be16 port;
+	__be16 port = cpu_to_be16(CIFS_PORT);
 
 	if (old->ss_family == AF_INET) {
 		struct sockaddr_in *ipv4 = (struct sockaddr_in *)old;
 
 		port = ipv4->sin_port;
-	}
-
-	if (old->ss_family == AF_INET6) {
+	} else if (old->ss_family == AF_INET6) {
 		struct sockaddr_in6 *ipv6 = (struct sockaddr_in6 *)old;
 
 		port = ipv6->sin6_port;
@@ -465,9 +463,7 @@ static int cifs_swn_store_swn_addr(const struct sockaddr_storage *new,
 		struct sockaddr_in *ipv4 = (struct sockaddr_in *)new;
 
 		ipv4->sin_port = port;
-	}
-
-	if (new->ss_family == AF_INET6) {
+	} else if (new->ss_family == AF_INET6) {
 		struct sockaddr_in6 *ipv6 = (struct sockaddr_in6 *)new;
 
 		ipv6->sin6_port = port;