[IPV6]: Fix ipv6 GSO payload length

Fix ipv6 GSO payload length calculation.

The ipv6 payload length excludes the ipv6 base header length and so
must be subtracted.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 file changed