drivers: platform: msm: qpnp-vibrator: Add sysfs interface for intensity

To control the Haptic intensity using sysfs interface.

Signed-off-by: SpaceKiller <alexisalbo.1@gmail.com>
prima: Increase MAX_CFG_INI_ITEMS

MAX_CFG_INI_ITEMS too small, must be at least 343

Change-Id: Ife5316cdd7577eba4a17bf05a071dc771f6d06df