net: sched: cls_cgroup: no need to call tcf_exts_change for newly allocated struct

net: sched: cls_cgroup: no need to call tcf_exts_change for newly allocated struct

As the new struct just was allocated, so no need to use tcf_exts_change
to do atomic change, and we can just fill-up the unused exts struct
directly by tcf_exts_validate.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>