e1000: Fix NAPI state bug when Rx complete

Don't exit polling when we have not yet used our budget, this causes
the NAPI system to end up with a messed up poll list.
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/net/e1000/e1000_main.c

@@ -3942,7 +3942,7 @@ e1000_clean(struct napi_struct *napi, int budget)
 	                  &work_done, budget);
 
 	/* If no Tx and not enough Rx work done, exit the polling mode */
-	if ((!tx_cleaned && (work_done < budget)) ||
+	if ((!tx_cleaned && (work_done == 0)) ||
 	   !netif_running(poll_dev)) {
 quit_polling:
 		if (likely(adapter->itr_setting & 3))