PM / tools: new tool for suspend/resume performance optimization

This tool is designed to assist kernel and OS developers in optimizing
their linux stack's suspend/resume time. Using a kernel image built with a
few extra options enabled, the tool will execute a suspend and will
capture dmesg and ftrace data until resume is complete. This data is
transformed into a device timeline and a callgraph to give a quick and
detailed view of which devices and callbacks are taking the most time in
suspend/resume. The output is a single html file which can be viewed in
firefox or chrome.

References: https://01.org/suspendresume
Signed-off-by: Todd Brandt <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>