net: sched: Using NULL instead of plain integer

Fixes the following sparse warnings:

net/sched/cls_api.c:1101:43: warning: Using plain integer as NULL pointer
net/sched/cls_api.c:1492:75: warning: Using plain integer as NULL pointer

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 file changed