net: Remove CONFIG_KMOD from net/ (towards removing CONFIG_KMOD entirely)

Some code here depends on CONFIG_KMOD to not try to load
protocol modules or similar, replace by CONFIG_MODULES
where more than just request_module depends on CONFIG_KMOD
and and also use try_then_request_module in ebtables.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/netfilter/nf_conntrack_netlink.c

@@ -822,7 +822,7 @@ ctnetlink_parse_nat_setup(struct nf_conn *ct,
 
 	parse_nat_setup = rcu_dereference(nfnetlink_parse_nat_setup_hook);
 	if (!parse_nat_setup) {
-#ifdef CONFIG_KMOD
+#ifdef CONFIG_MODULES
 		rcu_read_unlock();
 		nfnl_unlock();
 		if (request_module("nf-nat-ipv4") < 0) {

net/netfilter/nfnetlink.c

@@ -137,7 +137,7 @@ static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 replay:
 	ss = nfnetlink_get_subsys(type);
 	if (!ss) {
-#ifdef CONFIG_KMOD
+#ifdef CONFIG_MODULES
 		nfnl_unlock();
 		request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
 		nfnl_lock();