netfilter: connlabels: change nf_connlabels_get bit arg to 'highest used'

nf_connlabel_set() takes the bit number that we would like to set.
nf_connlabels_get() however took the number of bits that we want to
support.

So e.g. nf_connlabels_get(32) support bits 0 to 31, but not 32.
This changes nf_connlabels_get() to take the highest bit that we want
to set.

Callers then don't have to cope with a potential integer wrap
when using nf_connlabels_get(bit + 1) anymore.

Current callers are fine, this change is only to make folloup
nft ct label set support simpler.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c
index 1b9d286..e5fe24a 100644
--- a/net/openvswitch/conntrack.c
+++ b/net/openvswitch/conntrack.c
@@ -1344,7 +1344,7 @@
 	unsigned int n_bits = sizeof(struct ovs_key_ct_labels) * BITS_PER_BYTE;
 	struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
 
-	if (nf_connlabels_get(net, n_bits)) {
+	if (nf_connlabels_get(net, n_bits - 1)) {
 		ovs_net->xt_label = false;
 		OVS_NLERR(true, "Failed to set connlabel length");
 	} else {