netfilter: xt_quota2: 3.18 netlink notification fix

Create a virtual device inside of sysfs.  Use the created
kobject to notify userspace of counter transitions.

Bug: 24140541
CRs-Fixed: 1008025
Change-Id: I06a02a3e6c70160083e17291cf08f1e9b375a26f
Signed-off-by: Bryse Flowers <bflowers@codeaurora.org>