net: ena: fix rare bug when failed restart/resume is followed by driver removal

In a rare scenario when ena_device_restore() fails, followed by device
remove, an FLR will not be issued. In this case, the device will keep
sending asynchronous AENQ keep-alive events, even after driver removal,
leading to memory corruption.

Fixes: 8c5c7abd ("net: ena: add power management ops to the ENA driver")
Signed-off-by: Arthur Kiyanovski <akiyano@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>