net: sched: fix memory leak in tcindex_partial_destroy_work

Syzbot reported memory leak in tcindex_set_parms(). The problem was in
non-freed perfect hash in tcindex_partial_destroy_work().

In tcindex_set_parms() new tcindex_data is allocated and some fields from
old one are copied to new one, but not the perfect hash. Since
tcindex_partial_destroy_work() is the destroy function for old
tcindex_data, we need to free perfect hash to avoid memory leak.

Reported-and-tested-by:  <syzbot+f0bbb2287b8993d4fa74@syzkaller.appspotmail.com>
Fixes: 331b7292

 ("net: sched: RCU cls_tcindex")
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>