power: qpnp-qg: Replace ktime_get with ktime_get_boottime

ktime_get_boottime reports the time elapsed across suspend.
This is a required for QG where the system can go to suspend
across FIFO done events.

Change-Id: I3e51dc34cea5c97a7f901d9981f908e35b8b0fb8
Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>