octeontx2-pf: Fix TSOv6 offload

stable inclusion
from stable-v5.10.181
commit 72971f4071b49edd0823cc37019080486664a248
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8GJZJ

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=72971f4071b49edd0823cc37019080486664a248



--------------------------------

commit de678ca3 upstream.

HW adds segment size to the payload length
in the IPv6 header. Fix payload length to
just TCP header length instead of 'TCP header
size + IPv6 header size'.

Fixes: 86d74760 ("octeontx2-pf: TCP segmentation offload support")
Signed-off-by: Sunil Goutham <sgoutham@marvell.com>
Signed-off-by: Ratheesh Kannoth <rkannoth@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>
(cherry picked from commit 2845738b)