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

Change-Id: Icaad02fe1e8856fdc2e4215f380594a5dde8e002
Signed-off-by: Arve
Hjonnevag <arve@android.com>

idea is taken here -
https://github.com/rmbq/android_kernel_htc_msm8960/commit/332df913f2d62753b5631dba4daaa598fe0c040e