amd-xgbe: Clear all state during a device restart

When performing a device restart, like during an MTU change, sometimes
the device queues still have data and get hung up trying to flush
resulting in the device becoming unresponsive until brought down and
back up. To prevent this, always perform a device reset during a
restart.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>