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>
get_be16(const void **pp)
{
    const ovs_be16 *p = *pp;
    ovs_be16 value = *p;
    *pp = p + 1;
    return value;
}

get_be16(const void **pp)
{
    const ovs_be16 *p = *pp;
    ovs_be16 value = *p;
    *pp = p + 1;
    return value;
}
