NFC: llcp: two bugs in ->getname()

The sockaddr_nfc_llcp struct has as hole between ->sa_family and
->dev_idx so I've added a memset() to clear it and prevent an
information leak.

Also the ->nfc_protocol element wasn't set so I've added that.

"uaddr->sa_family" and "llcp_addr->sa_family" are the same thing but
it's less confusing to use llcp_addr consistently throughout.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>