net: hns3: fix pause config problem after autoneg disabled

commit 3bda2e5d upstream.

If a TP port is configured by follow steps:
1.ethtool -s ethx autoneg off speed 100 duplex full
2.ethtool -A ethx rx on tx on
3.ethtool -s ethx autoneg on(rx&tx negotiated pause results are off)
4.ethtool -s ethx autoneg off speed 100 duplex full

In step 3, driver will set rx&tx pause parameters of hardware to off as
pause parameters negotiated with link partner are off.

After step 4, the "ethtool -a ethx" command shows both rx and tx pause
parameters are on. However, pause parameters of hardware are still off
and port has no flow control function actually.

To fix this problem, if autoneg is disabled, driver uses its saved
parameters to restore pause of hardware. If the speed is not changed in
this case, there is no link state changed for phy, it will cause the pause
parameter is not taken effect, so we need to force phy to go down and up.

Fixes: aacbe27e ("net: hns3: modify how pause options is displayed")
Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>