tools lib traceevent: Support %ps/%pS

Commits such as 65dd297a

 ("xfs: %pF is only for function
pointers") caused a regression because pretty_print() didn't support
%ps/%pS.  The current %pf/%pF implementation in pretty_print() is what
%ps/%pS is supposed to do, so use the same code for %ps/%pS.

Addressing the incorrect %pf/%pF implementation is beyond the scope of
this patch.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Dave Chinner <david@fromorbit.com>
Link: http://lkml.kernel.org/r/20150831211637.GA12848@home.buserror.net
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>