ftracetest: Add ftrace basic testcases

Add ftrace basic testcases. This just checks ftrace debugfs
interface works as it is designed.

Link: http://lkml.kernel.org/p/20140922234252.23415.62897.stgit@kbuild-f20.novalocal

Acked-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

tools/testing/selftests/ftrace/test.d/00basic/basic3.tc

@@ -0,0 +1,8 @@
+#!/bin/sh
+# description: Basic trace clock test
+[ -f trace_clock ] || exit 1
+for c in `cat trace_clock | tr  -d \[\]`; do
+  echo $c > trace_clock || exit 1
+  grep '\['$c'\]' trace_clock || exit 1
+done
+echo local > trace_clock