netfilter: flowtable: pass flowtable to nf_flow_table_iterate()

[ Upstream commit 217cff36

 ]

The flowtable object is already passed as argument to
nf_flow_table_iterate(), do use not data pointer to pass flowtable.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>