Revert "r8169: don't try to disable interrupts if NAPI is, scheduled already"

This reverts commit 7274c41.

Ken reported that RTL8125b can lock up if gro_flush_timeout has the
default value of 20000 and napi_defer_hard_irqs is set to 0.
In this scenario device interrupts aren't disabled, what seems to
trigger some silicon bug under heavy load. I was able to reproduce this
behavior on RTL8168h. Fix this by reverting 7274c41.

Fixes: 7274c41 ("r8169: don't try to disable interrupts if NAPI is scheduled already")
Cc: stable@vger.kernel.org
Reported-by: Ken Milmore <ken.milmore@gmail.com>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/9b5b6f4c-4f54-4b90-b0b3-8d8023c2e780@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Author: hkallweit

drivers/net/ethernet/realtek/r8169_main.c

@@ -4657,10 +4657,8 @@ static irqreturn_t rtl8169_interrupt(int irq, void *dev_instance)
 		rtl_schedule_task(tp, RTL_FLAG_TASK_RESET_PENDING);
 	}
 
-	if (napi_schedule_prep(&tp->napi)) {
-		rtl_irq_disable(tp);
-		__napi_schedule(&tp->napi);
-	}
+	rtl_irq_disable(tp);
+	napi_schedule(&tp->napi);
 out:
 	rtl_ack_events(tp, status);