put iov_iter into msghdr

Note that the code _using_ ->msg_iter at that point will be very
unhappy with anything other than unshifted iovec-backed iov_iter.
We still need to convert users to proper primitives.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c
index bdcaefd..d8c67a5e 100644
--- a/net/bluetooth/6lowpan.c
+++ b/net/bluetooth/6lowpan.c
@@ -537,12 +537,12 @@
 	 */
 	chan->data = skb;
 
-	memset(&msg, 0, sizeof(msg));
-	msg.msg_iov = (struct iovec *) &iv;
-	msg.msg_iovlen = 1;
 	iv.iov_base = skb->data;
 	iv.iov_len = skb->len;
 
+	memset(&msg, 0, sizeof(msg));
+	iov_iter_init(&msg.msg_iter, WRITE, (struct iovec *) &iv, 1, skb->len);
+
 	err = l2cap_chan_send(chan, &msg, skb->len);
 	if (err > 0) {
 		netdev->stats.tx_bytes += err;