perf test: 'unwind' test should create kernel maps

The 'perf test unwind' is failing because it forgot to create the kernel
maps, fix it.

After the patch:

  # perf test unwind
  40: Test dwarf unwind         : Ok
Reported-and-Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/20151127082121.GA24503@krava.brq.redhat.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/tests/dwarf-unwind.c

@@ -173,6 +173,11 @@ int test__dwarf_unwind(int subtest __maybe_unused)
 		return -1;
 	}
 
+	if (machine__create_kernel_maps(machine)) {
+		pr_err("Failed to create kernel maps\n");
+		return -1;
+	}
+
 	callchain_param.record_mode = CALLCHAIN_DWARF;
 
 	if (init_live_machine(machine)) {