[NET]: kfree cleanup

From: Jesper Juhl <jesper.juhl@gmail.com>

This is the net/ part of the big kfree cleanup patch.

Remove pointless checks for NULL prior to calling kfree() in net/.

Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Arnaldo Carvalho de Melo <acme@conectiva.com.br>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Acked-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>