gianfar: Wait for both RX and TX to stop

When gracefully stopping the controller, the driver was continuing if
*either* RX or TX had stopped.  We need to wait for both, or the
controller could get into an invalid state.

Signed-off-by: Andy Fleming <afleming@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/gianfar.c b/drivers/net/gianfar.c
index df49af3..4e97ca1 100644
--- a/drivers/net/gianfar.c
+++ b/drivers/net/gianfar.c
@@ -1511,9 +1511,9 @@
 		tempval |= (DMACTRL_GRS | DMACTRL_GTS);
 		gfar_write(&regs->dmactrl, tempval);
 
-		while (!(gfar_read(&regs->ievent) &
-			 (IEVENT_GRSC | IEVENT_GTSC)))
-			cpu_relax();
+		spin_event_timeout(((gfar_read(&regs->ievent) &
+			 (IEVENT_GRSC | IEVENT_GTSC)) ==
+			 (IEVENT_GRSC | IEVENT_GTSC)), -1, 0);
 	}
 }