igb: remove use of skb_dma_map from driver

This change removes skb_dma_map/unmap calls from the igb driver due to the
fact that the call is incompatible with iommu enabled kernels.  In order to
prevent warnings about using the wrong unmap call I have added a
mapped_as_page value to the buffer_info structure to track if the mapped
region is a page or a buffer.

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/igb/igb.h

@@ -137,12 +137,13 @@ struct igb_buffer {
 			unsigned long time_stamp;
 			u16 length;
 			u16 next_to_watch;
+			u16 mapped_as_page;
 		};
 		/* RX */
 		struct {
 			struct page *page;
-			u64 page_dma;
-			unsigned int page_offset;
+			dma_addr_t page_dma;
+			u16 page_offset;
 		};
 	};
 };