power: smb5-lib: Fix wake lock acquisition

Currently, pm_stay_awake and pm_relax are called directly from the
alarm callback routines since we are in atomic context. However,
pm_stay_awake/pm_relax are not ref counted which leaves a possibility
of the wakelock being cleared by any other thread of this module.

Fix this by explicitly voting to awake votable, to ensure pm_relax
isn't called before the complete execution of the routine.

Change-Id: I3b28315648261eacfa3247d8fcb76673d506629b
Signed-off-by: Umang Agrawal <uagrawal@codeaurora.org>