netfilter: nf_tables: fix trace of matching non-terminal rule

Add the corresponding trace if we have a full match in a non-terminal
rule. Note that the traces will look slightly different than in
x_tables since the log message after all expressions have been
evaluated (contrary to x_tables, that emits it before the target
action). This manifests in two differences in nf_tables wrt. x_tables:

1) The rule that enables the tracing is included in the trace.

2) If the rule emits some log message, that is shown before the
   trace log message.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nf_tables_core.c

@@ -144,8 +144,10 @@ nft_do_chain(struct nft_pktinfo *pkt, const struct nf_hook_ops *ops)
 		switch (data[NFT_REG_VERDICT].verdict) {
 		case NFT_BREAK:
 			data[NFT_REG_VERDICT].verdict = NFT_CONTINUE;
-			/* fall through */
+			continue;
 		case NFT_CONTINUE:
+			if (unlikely(pkt->skb->nf_trace))
+				nft_trace_packet(pkt, chain, rulenum, NFT_TRACE_RULE);
 			continue;
 		}
 		break;