vibrator: Add support for duration based amplitude control

 * Similar to what samsung is doing on devices without hardware intensity control.
 * Add `$(call soong_config_set,samsungVibratorVars,duration_amplitude,true)` in BoardConfig.mk to enable.

Change-Id: I87a767e00363c36f8bd4d61cb6dd23b5c033a3d3
3 files changed