Clean up a really messy cross reference where a macro cls_set_class
in pkt_sched.h would point to a function tcf_set_class in cls_api.c
that uses a inlined function __cls_set_class in pkt_sched.h again.

Make tcf_set_class be cls_set_class since it was never used and
inline it as well.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>