The jumbo offload was removed from patch [1], but testpmd still exist
jumbo offload related code, this patch removes it, and also updates
the rst file.
[1] ethdev: remove jumbo offload flag
Fixes: b563c14212 ("ethdev: remove jumbo offload flag")
Cc: stable@dpdk.org
Signed-off-by: Chengwen Feng <fengchengwen@huawei.com>
Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>