tools lib traceevent: If %s is a pointer, check printk formats

If the format string of TP_printk() contains a %s, and the argument is
not a string, check if the argument is a pointer that might match the
printk_formats that were stored.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/20131101215500.698924777@goodmis.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>