staging: rtl8712u: Fix compiler warning about strncpy

When strncpy() is called with source and destination strings the same
length, gcc 8 warns that there may be an unterminated string. Using
strlcpy() rather than strncpy() forces a null at the end and quiets the
warning.
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8712/rtl871x_ioctl_linux.c

@@ -1784,7 +1784,7 @@ static int r871x_wx_set_enc_ext(struct net_device *dev,
 		return -ENOMEM;
 	param->cmd = IEEE_CMD_SET_ENCRYPTION;
 	eth_broadcast_addr(param->sta_addr);
-	strncpy((char *)param->u.crypt.alg, alg_name, IEEE_CRYPT_ALG_NAME_LEN);
+	strlcpy((char *)param->u.crypt.alg, alg_name, IEEE_CRYPT_ALG_NAME_LEN);
 	if (pext->ext_flags & IW_ENCODE_EXT_GROUP_KEY)
 		param->u.crypt.set_tx = 0;
 	if (pext->ext_flags & IW_ENCODE_EXT_SET_TX_KEY)