[LRO]: fix lro_gen_skb() alignment

Add a field to the lro_mgr struct so that drivers can specify how much
padding is required to align layer 3 headers when a packet is copied
into a freshly allocated skb by inet_lro.c:lro_gen_skb().  Without
padding, skbs generated by LRO will cause alignment warnings on
architectures which require strict alignment (seen on sparc64).

Myri10GE is updated to use this field.

Signed-off-by: Andrew Gallatin <gallatin@myri.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/myri10ge/myri10ge.c b/drivers/net/myri10ge/myri10ge.c
index 0f306dd..8def865 100644
--- a/drivers/net/myri10ge/myri10ge.c
+++ b/drivers/net/myri10ge/myri10ge.c
@@ -1979,6 +1979,7 @@
 	lro_mgr->lro_arr = mgp->rx_done.lro_desc;
 	lro_mgr->get_frag_header = myri10ge_get_frag_header;
 	lro_mgr->max_aggr = myri10ge_lro_max_pkts;
+	lro_mgr->frag_align_pad = 2;
 	if (lro_mgr->max_aggr > MAX_SKB_FRAGS)
 		lro_mgr->max_aggr = MAX_SKB_FRAGS;