perf timechart: Show the duration of scheduler delays in the SVG

Given that scheduler latencies are the hot thing nowadays, show the
duration of said latencies in the SVG in text form.

In addition, if the latency is more than 10 msec, pick a brighter
yellow color as a way to point these long delays out.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20090920181353.796f4509@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>