[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/net/ipv4/inet_lro.c b/net/ipv4/inet_lro.c
index ac3b1d3..9a96c27 100644
--- a/net/ipv4/inet_lro.c
+++ b/net/ipv4/inet_lro.c
@@ -401,10 +401,11 @@
 	int data_len = len;
 	int hdr_len = min(len, hlen);
 
-	skb = netdev_alloc_skb(lro_mgr->dev, hlen);
+	skb = netdev_alloc_skb(lro_mgr->dev, hlen + lro_mgr->frag_align_pad);
 	if (!skb)
 		return NULL;
 
+	skb_reserve(skb, lro_mgr->frag_align_pad);
 	skb->len = len;
 	skb->data_len = len - hdr_len;
 	skb->truesize += true_size;