input: sensors: add sensors class support for apds9930

The userspace sensor HAL uses sensors class to interact with linux
kernel drivers. Thus add this feature in order to enable the ALPS
sensor.

Change-Id: I4e2f12b4a3cd4d24a84b82f2584752aceec3cd0a
Signed-off-by: Oliver Wang <mengmeng@codeaurora.org>