net_sched: expand control flow of macro SKIP_NONLOCAL

SKIP_NONLOCAL hides the control flow. The control flow should be
inlined and expanded explicitly in code so that someone who reads
it can tell the control flow can be changed by the statement.

Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>