e1000e: do not disable receiver on 82574/82583

Due to a hardware erratum, the receiver on 82574 and 82583 should not be
stopped once it has been started.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/drivers/net/e1000e/ethtool.c b/drivers/net/e1000e/ethtool.c
index 06d88f3..6a0526a 100644
--- a/drivers/net/e1000e/ethtool.c
+++ b/drivers/net/e1000e/ethtool.c
@@ -1206,7 +1206,8 @@
 	rx_ring->next_to_clean = 0;
 
 	rctl = er32(RCTL);
-	ew32(RCTL, rctl & ~E1000_RCTL_EN);
+	if (!(adapter->flags2 & FLAG2_NO_DISABLE_RX))
+		ew32(RCTL, rctl & ~E1000_RCTL_EN);
 	ew32(RDBAL, ((u64) rx_ring->dma & 0xFFFFFFFF));
 	ew32(RDBAH, ((u64) rx_ring->dma >> 32));
 	ew32(RDLEN, rx_ring->size);