selftests: ftrace: Add a testcase for types of kprobe event

Add a testcase for types of kprobe event. This checks
kprobe event can accept and correctly expressed the
arguments typed as s32, u32, x32 and bitfield.

Here is the test result.
  -----
  # ./ftracetest test.d/kprobe/kprobe_args_type.tc
  === Ftrace unit tests ===
  [1] Kprobes event arguments with types	[PASS]

  # of passed:  1
  # of failed:  0
  # of unresolved:  0
  # of untested:  0
  # of unsupported:  0
  # of xfailed:  0
  # of undefined(test bug):  0
  -----

Link: http://lkml.kernel.org/r/147928409063.22982.3499119203875115458.stgit@devbox



Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>