netfilter: synproxy: ensure zero is returned on non-error return path
Currently functions nf_synproxy_{ipc4|ipv6}_init return an uninitialized
garbage value in variable ret on a successful return. Fix this by
returning zero on success.
Addresses-Coverity: ("Uninitialized scalar variable") Fixes: d7f9b2f18eae ("netfilter: synproxy: extract SYNPROXY infrastructure from {ipt, ip6t}_SYNPROXY") Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>