tspdrv: add userspace vibration strength control (1/2)

Change-Id: Ie0941223f07a5df6baadad6b8228cc91710040c9
Signed-off-by: Park Ju Hyung <qkrwngud825@gmail.com>

Code clean-ups & vibration strength over stock 126 value
Signed-off-by: Jean-Pierre Rasquin <yank555.lu@gmail.com>