Without this change it fails to build from source:
client_switch.c:80:1:\
error: ‘put_light’ defined but not used [-Werror=unused-function]
At least with BOARD=arduino-mega2560, now all iotivity examples are building.
Bug: https://github.com/RIOT-OS/RIOT/issues/6241
Change-Id: I6b2af5ab6b8bf20e848dcd30d580990006c950e7
Signed-off-by: Philippe Coval <philippe.coval@osg.samsung.com>