PM / Sleep: Add wake lock api wrapper on top of wakeup sources

Change-Id: Icaad02fe1e8856fdc2e4215f380594a5dde8e002
Signed-off-by: Arve Hjønnevåg <arve@android.com>
Git-commit: e9911f4efdc55af703b8b3bb8c839e6f5dd173bb
Git-repo: git://codeaurora.org/kernel/msm.git
[anursing@codeaurora.org: replace existing implementation, resolve
merge conflicts]
Signed-off-by: Anurag Singh <anursing@codeaurora.org>

Conflicts:

	include/linux/wakelock.h
	kernel/power/Kconfig