netfilter: nf_nat_snmp_basic: fix a range check in NAT for SNMP

netfilter: nf_nat_snmp_basic: fix a range check in NAT for SNMP

commit 252815b0cfe711001eff0327872209986b36d490 upstream

Fix a range check in netfilter IP NAT for SNMP to always use a big enough size
variable that the compiler won't moan about comparing it to ULONG_MAX/8 on a
64-bit platform.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Eugene Teo <eteo@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>