tspdrv: Add LG's timed_output based interface

Change-Id: I43383ad9e0ba4e0ba13837c0741885162cf40b63

 This is the 2nd commit message:

 tspdrv: Make the timed state atomic

 This should fix race conditions with fast bursts of short tones

Change-Id: I2c369da0a80dedebf7346613437d2b69d6a92c3c

 This is the 3rd commit message:

 tspdrv: Add a sysfs control for timed vibrator strength

Change-Id: I66dec312e52a3c8834a93f6b8970c94a0d6af923