macsec: fix validation failed in asynchronous operation.

MACSec test failed when asynchronous crypto operations is used. It
encounters packet validation failed since macsec_skb_cb(skb)->valid
is always 'false'.

This patch adds missing "macsec_skb_cb(skb)->valid = true" in
macsec_decrypt_done() when "err == 0".

Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/macsec.c

@@ -879,6 +879,9 @@ static void macsec_decrypt_done(struct crypto_async_request *base, int err)
 
 	aead_request_free(macsec_skb_cb(skb)->req);
 
+	if (!err)
+		macsec_skb_cb(skb)->valid = true;
+
 	rcu_read_lock_bh();
 	pn = ntohl(macsec_ethhdr(skb)->packet_number);
 	if (!macsec_post_decrypt(skb, &macsec->secy, pn)) {