e1000: driver state fixes (race fix)

We were plagued by our interrupt handler posting a watchdog event which
could occur when our adapter was going down in case a late packet arrived
just before e1000_down() finished. This caused the watchdog timer to start
after the NIC was down and keep rescheduling it every N seconds. Once
the driver unloaded it would panic.

Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>

drivers/net/e1000/e1000.h

@@ -345,8 +345,9 @@ struct e1000_adapter {
 };
 
 enum e1000_state_t {
-	__E1000_DRIVER_TESTING,
+	__E1000_TESTING,
 	__E1000_RESETTING,
+	__E1000_DOWN
 };
 
 #endif /* _E1000_H_ */