netfilter: nf_tables: Fix a use after free in nft_immediate_destroy()

The nf_tables_rule_release() function frees "rule" so we have to use
the _safe() version of list_for_each_entry().

Fixes: d0e2c7de

 ("netfilter: nf_tables: add NFT_CHAIN_BINDING")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>