NET: llc, zero sockaddr_llc struct

commit 28e9fc59 upstream.

sllc_arphrd member of sockaddr_llc might not be changed. Zero sllc
before copying to the above layer's structure.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>