IP_TRANSPARENT requires root (more precisely CAP_NET_ADMIN privielges)
for IPV6.

However as I see right now this check was missed from the IPv6
implementation.
Acked-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>