[NETLINK]: Remove error pointer from netlink message handler

The error pointer argument in netlink message handlers is used
to signal the special case where processing has to be interrupted
because a dump was started but no error happened. Instead it is
simpler and more clear to return -EINTR and have netlink_run_queue()
deal with getting the queue right.

nfnetlink passed on this error pointer to its subsystem handlers
but only uses it to signal the start of a netlink dump. Therefore
it can be removed there as well.

This patch also cleans up the error handling in the affected
message handlers to be consistent since it had to be touched anyway.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c
index 9709f94..b174aad 100644
--- a/net/netfilter/nfnetlink_log.c
+++ b/net/netfilter/nfnetlink_log.c
@@ -759,7 +759,7 @@
 
 static int
 nfulnl_recv_unsupp(struct sock *ctnl, struct sk_buff *skb,
-		  struct nlmsghdr *nlh, struct nfattr *nfqa[], int *errp)
+		  struct nlmsghdr *nlh, struct nfattr *nfqa[])
 {
 	return -ENOTSUPP;
 }
@@ -797,7 +797,7 @@
 
 static int
 nfulnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
-		   struct nlmsghdr *nlh, struct nfattr *nfula[], int *errp)
+		   struct nlmsghdr *nlh, struct nfattr *nfula[])
 {
 	struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
 	u_int16_t group_num = ntohs(nfmsg->res_id);