netfilter: nfnetlink_acct: add filter support to nfacct counter list/reset

netfilter: nfnetlink_acct: add filter support to nfacct counter list/reset

You can use this to skip accounting objects when listing/resetting
via NFNL_MSG_ACCT_GET/NFNL_MSG_ACCT_GET_CTRZERO messages with the
NLM_F_DUMP netlink flag. The filtering covers the following cases:

1. No filter specified. In this case, the client will get old behaviour,
2. List/reset counter object only: In this case, you have to use
   NFACCT_F_QUOTA as mask and value 0.
3. List/reset quota objects only: You have to use NFACCT_F_QUOTA_PKTS
   as mask and value - the same, for byte based quota mask should be
   NFACCT_F_QUOTA_BYTES and value - the same.

If you want to obtain the object with any quota type
(ie. NFACCT_F_QUOTA_PKTS|NFACCT_F_QUOTA_BYTES), you need to perform
two dump requests, one to obtain NFACCT_F_QUOTA_PKTS objects and
another for NFACCT_F_QUOTA_BYTES.

Signed-off-by: Alexey Perevalov <a.perevalov@samsung.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>