perf: Allow perf utilities to have "callback" options without arguments

timechart needs to add a "callback" type command line argument that
does not take arguments.

This patch adds the parse-options.h infrastructure to make this
possible.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20090912130440.548666c1@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>