e1000: remove use of skb_dma_map from e1000 driver

Remove the use of skb_dma_map from the e1000 driver in order to avoid
issues when HW iommu are in use.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/e1000/e1000.h

@@ -167,6 +167,7 @@ struct e1000_buffer {
 	unsigned long time_stamp;
 	u16 length;
 	u16 next_to_watch;
+	u16 mapped_as_page;
 };
 
 struct e1000_tx_ring {