Also add a comment in nla_align_64bit() explaining we have
to add a padding if current skb->data is aligned, as it
certainly can be confusing.
Fixes: 35c5845957c7 ("net: Add helpers for 64-bit aligning netlink attributes.") Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>