msm: pm-8x60: Use ktime_get for suspend stats

During suspend, the sched clock is stopped and the suspends ops
cannot rely on sched clock to report time spent in suspend. Use ktime
interface to determine the time spent in suspend.

Change-Id: Id244cd8d470c45c1edd408e98ccaf84d30c3e253
Signed-off-by: Mahesh Sivasubramanian <msivasub@codeaurora.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>