net: sched: cls_api: Fix the the wrong parameter

The 4th parameter in tc_chain_notify() should be flags rather than seq.
Let's change it back correctly.

Fixes: 32a4f5ec

 ("net: sched: introduce chain object to uapi")
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Signed-off-by: David S. Miller <davem@davemloft.net>