(commit 70837ffe upstream)

We accidentally removed the parentheses here, but they are required
because '!' has higher precedence than '&'.

Fixes: fa0f5273 ("ip: use rb trees for IP frag queue.")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>