[LLC]: Fix the accept path

Borrowing the structure of TCP/IP for this. On the receive of new connections I
was bh_lock_socking the _new_ sock, not the listening one, duh, now it survives
the ssh connections storm I've been using to test this specific bug.

Also fixes send side skb sock accounting.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>