core: common: Remove specific code for RIOT
core: common: Remove specific code for RIOT

Signed-off-by: Francois Berder <0eabc3e9da54407da074ac08d4217d54f5b94915@imgtec.com>

FlowM2M/AwaLWM2M,FlowM2M/AwaLWM2M,FlowM2M/AwaLWM2M,FlowM2M/AwaLWM2M