e1000: fix tx waking queue after queue stopped during shutdown

This fix closes a race where the adapter can be shutting down while
hard_start_xmit is being called and interrupts are being handled.

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Don Skidmore <donald.c.skidmore@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>