power_Resume: report time to bring all cpus online

look for the last instance of "CPUn is up" and subtract the resume begin from there

BUG=13649
TEST=run power_Resume and check for the presense of the resume_kernel_cpu metric

Change-Id: I3e03e4a3faea7772f5557dcbe21a5d9d0ca836f6

R=bleung@chromium.org,snanda@chromium.org

Review URL: http://codereview.chromium.org/6756015
1 file changed