ofp-actions: Avoid buffer overread in BUNDLE action decoding.

Reported-at: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=9052
Signed-off-by: Ben Pfaff <blp@ovn.org>
Acked-by: Justin Pettit <jpettit@ovn.org>
encode_DEC_MPLS_TTL(const struct ofpact_null *null OVS_UNUSED,
                    enum ofp_version ofp_version, struct ofpbuf *out)
{
    put_OFPAT_DEC_MPLS_TTL(out, ofp_version);
}

encode_DEC_MPLS_TTL(const struct ofpact_null *null OVS_UNUSED,
                    enum ofp_version ofp_version, struct ofpbuf *out)
{
    put_OFPAT_DEC_MPLS_TTL(out, ofp_version);
}
