When an skb with a frag list is consumed, we currently
pretend all skbs in the frag list were dropped.

In order to fix this, add a @reason argument to skb_release_data()
and skb_release_all().
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>