bna: fix skb->truesize underestimation

skb->truesize is not meant to be tracking amount of used bytes
in an skb, but amount of reserved/consumed bytes in memory.

For instance, if we use a single byte in last page fragment,
we have to account the full size of the fragment.

skb->truesize can be very different from skb->len, that has
a very specific safety purpose.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Rasesh Mody <rasesh.mody@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/brocade/bna/bnad.c

@@ -552,6 +552,7 @@ bnad_cq_setup_skb_frags(struct bna_rcb *rcb, struct sk_buff *skb,
 
 		len = (vec == nvecs) ?
 			last_fraglen : unmap->vector.len;
+		skb->truesize += unmap->vector.len;
 		totlen += len;
 
 		skb_fill_page_desc(skb, skb_shinfo(skb)->nr_frags,
@@ -563,7 +564,6 @@ bnad_cq_setup_skb_frags(struct bna_rcb *rcb, struct sk_buff *skb,
 
 	skb->len += totlen;
 	skb->data_len += totlen;
-	skb->truesize += totlen;
 }
 
 static inline void