perf tools: Add empty rule for new line in event syntax parsing

The flex generator prints out each input character that is ignored by
lex rules.

Since the alias processing, we can have '\n' characters on input. We
need to assign empty rule to it, so it's not printed out.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1341352848-11833-2-git-send-email-jolsa@redhat.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>