Add ftrace event trace_cpuhp_latency to track cpu hotplug latency and this entry is useful in power, performance and debug analysis. Change-Id: Ie6b2a91027c665ccaf6325b0836bb629a4e91dd7 Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org> Signed-off-by: Venkata Narendra Kumar Gutta <vnkgutta@codeaurora.org>