leds: qpnp: add driver file for configuring Vibrator LDO

Add a platform driver for configuring QPNP Vibrator LDO
HW module. The driver registers to leds framework and
exposes device attributes such as state, duration, activate
and vmax_uv.

CRs-Fixed: 2165526
Change-Id: Ib18fb4bdb6e412e7ef8b094501e0e0f8c89a2077
Signed-off-by: Tirupathi Reddy <tirupath@codeaurora.org>