input: sensors: change sensors classdev device's parent to input devices

Sensor HAL takes long time to scan /dev/input to get information
from input subsystem. Change the sensors sysfs hierarchy to avoid
the scanning to reduce sensor HAL initialization time.

This patch is propagated from msm-3.10 kernel.
(commit: ea0c4e425a891a8cec1eaa84a79f7a314cee397a
input: sensors: change sensors classdev device's parent to input devices)

Change-Id: Ifcd560dacdba2600f2ae5d40a5c3e639ea291274
Signed-off-by: Sudhakar Manapati <smanap@codeaurora.org>