[igbvf] Remove some unused Linux-specific portions of igbvf.h

These unused portions trigger a compiler warning under gcc 4.6, due to
the ambiguity over the "page" field in struct igbvf_buffer.

Reported-by: Ralph Giles <giles@thaumas.net>
Tested-by: Ralph Giles <giles@thaumas.net>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/drivers/net/igbvf/igbvf.h

  * so a DMA handle can be stored along with the buffer
  */
 struct igbvf_buffer {
+#if 0
 	dma_addr_t dma;
 	dma_addr_t page_dma;
 	struct sk_buff *skb;
 		};
 	};
 	struct page *page;
+#endif
 };
 
 struct igbvf_ring {
+#if 0
 	struct igbvf_adapter *adapter;  /* backlink */
 	void *desc;			/* pointer to ring memory  */
 	dma_addr_t dma;			/* phys address of ring    */
 
 	/* array of buffer information structs */
 	struct igbvf_buffer *buffer_info;
-#if 0
 	struct napi_struct napi;
 
 	char name[IFNAMSIZ + 5];
-#endif
 	u32 eims_value;
 	u32 itr_val;
 	u16 itr_register;
 	struct sk_buff *rx_skb_top;
 
 	struct igbvf_queue_stats stats;
+#endif
 };
 
 /* board specific private data structure */