Limit sysctl_tcp_mem and sysctl_udp_mem initializers to prevent integer overflows.

Limit sysctl_tcp_mem and sysctl_udp_mem initializers to prevent integer overflows.

[ Upstream fixed this in a different way as parts of the commits:
	8d987e5c7510 (net: avoid limits overflow)
	a9febbb4bd13 (sysctl: min/max bounds are optional)
	27b3d80a7b6a (sysctl: fix min/max handling in __do_proc_doulongvec_minmax())
 -DaveM ]

On a 16TB x86_64 machine, sysctl_tcp_mem[2], sysctl_udp_mem[2], and
sysctl_sctp_mem[2] can integer overflow.  Set limit such that they are
maximized without overflowing.

Signed-off-by: Robin Holt <holt@sgi.com>
To: "David S. Miller" <davem@davemloft.net>
Cc: Willy Tarreau <w@1wt.eu>
Cc: linux-kernel@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: linux-sctp@vger.kernel.org
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: "Pekka Savola (ipv6)" <pekkas@netcore.fi>
Cc: James Morris <jmorris@namei.org>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Patrick McHardy <kaber@trash.net>
Cc: Vlad Yasevich <vladislav.yasevich@hp.com>
Cc: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>