tipc: fix a bit overflow in tipc_crypto_key_rcv()

msg_data_sz return a 32bit value, but size is 16bit. This may lead to a
bit overflow.
Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/tipc/crypto.c

@@ -2276,7 +2276,7 @@ static bool tipc_crypto_key_rcv(struct tipc_crypto *rx, struct tipc_msg *hdr)
 	struct tipc_crypto *tx = tipc_net(rx->net)->crypto_tx;
 	struct tipc_aead_key *skey = NULL;
 	u16 key_gen = msg_key_gen(hdr);
-	u16 size = msg_data_sz(hdr);
+	u32 size = msg_data_sz(hdr);
 	u8 *data = msg_data(hdr);
 	unsigned int keylen;