app/testpmd: retain all original dev conf when config DCB
app/testpmd: retain all original dev conf when config DCB

When configuring DCB, testpmd retains the rx_mode/tx_mode configuration in
rte_port->dev_conf. But some configurations, such as the link_speed, were
not saved if they were set before configuring DCB.

Fixes: 1a572499beb6 ("app/testpmd: setup DCB forwarding based on traffic class")
Cc: stable@dpdk.org

Signed-off-by: Huisong Li <6909b08cc600214438d1cc25e31062c8d1c2efdc@huawei.com>
Signed-off-by: Min Hu (Connor) <f02e10cb0a484c51b0f8634f83fbb4ab9ded1c6a@huawei.com>
Acked-by: Xiaoyun Li <151cc00bdba86cfa2ecfc39aaa98def8f092d9d8@intel.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk