timer: Fix incorrect merge resolution

Merge conflict resolution in commit 5682ea9f
("Merge remote-tracking branch 'remotes/origin/tmp-91891413' into msm-4.14")
has removed necessary changes in timer code.
This change adds the missing code back and fix the resolution in a
correct way.

Change-Id: I4b3994f535d559a6392a7174d6a32e43004c209c
Signed-off-by: Runmin Wang <runminw@codeaurora.org>