input: sensors: add sensor class support for lis3dh accelerometer

The userspace sensor HAL use sensors class to interact with linux
kernel drivers. This support is added to enable the lis3dh
accelerometer.

Change-Id: I6954e81803306df53ed362f3d079c0610a046240
Signed-off-by: Bingzhe Cai <bingzhec@codeaurora.org>