perf tools: Honour the cpu list parameter when also monitoring a thread list

The perf_evlist__create_maps was discarding the --cpu parameter when a
--pid or --tid was specified, fix that.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Link: http://lkml.kernel.org/r/20110426204401.GB1746@ghostprotocols.netSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/evlist.c

@@ -348,7 +348,7 @@ int perf_evlist__create_maps(struct perf_evlist *evlist, pid_t target_pid,
 	if (evlist->threads == NULL)
 		return -1;
 
-	if (target_tid != -1)
+	if (cpu_list == NULL && target_tid != -1)
 		evlist->cpus = cpu_map__dummy_new();
 	else
 		evlist->cpus = cpu_map__new(cpu_list);