pkt_sched: Add lockdep annotation for qdisc locks

Qdisc locks are initialized in the same function, qdisc_alloc(), so
lockdep can't distinguish tx qdisc lock from rx and reports "possible
recursive locking detected" when both these locks are taken eg. while
using act_mirred with ifb. This looks like a false positive. Anyway,
after this patch these locks will be reported more exactly.

Reported-by: Denys Fedoryshchenko <denys@visp.net.lb>
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>