net: sched: don't expose action qstats to skb_tc_reinsert()

[ Upstream commit ef816f3c ]

Previous commit introduced helper function for updating qstats and
refactored set of actions to use the helpers, instead of modifying qstats
directly. However, one of the affected action exposes its qstats to
skb_tc_reinsert(), which then modifies it.

Refactor skb_tc_reinsert() to return integer error code and don't increment
overlimit qstats in case of error, and use the returned error code in
tcf_mirred_act() to manually increment the overlimit counter with new
helper function.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[ skulkarni: Adjusted patch for file 'sch_generic.h' wrt the mainline commit ]
Stable-dep-of: ca22da2f ("act_mirred: use the backlog for nested calls to mirred ingress")
Signed-off-by: Shubham Kulkarni <skulkarni@mvista.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>