tools lib traceevent: Add support for "%.*s" in bprintk events

The arg notation of '*' in bprintks is not handled by the parser.
Implement it so that they show up properly in the output and do not
kill the tracer from reporting events.

Reported-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/n/tip-t0ctq7t1xz3ud6wv4v886jou@git.kernel.org


Signed-off-by: Namhyung Kim <namhyung@kernel.org>