act_mirred: combine duplicate code

tcf_bstats is updated in any way, so we can do it earlier to reduce the size of
the code.
Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
----
 net/sched/act_mirred.c |    6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)
Signed-off-by: David S. Miller <davem@davemloft.net>