perf timechart: Fix rendering in Firefox

Firefox doesn't correctly handle cases where we specify number in
quotes and have some padding around the number, like the following:
<rect ... height=" 3.1" ...>
In this case, it doesn't draw the figure. This patch removes 'field width'
component from fprintf strings to fix it.
Signed-off-by: Stanislav Fomichev <stfomichev@yandex-team.ru>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/n/1404835423-23098-2-git-send-email-stfomichev@yandex-team.ruSigned-off-by: Jiri Olsa <jolsa@kernel.org>