lwm2m: handle return code from lwm2m_socket_add
lwm2m: handle return code from lwm2m_socket_add

Handle return code from lwm2m_socket_add

Signed-off-by: Kiril Petrov <107338d8e53750e9172859f7bc39ad67ac7af543@gmail.com>

finikorg/zephyr,galak/zephyr,nashif/zephyr,finikorg/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,finikorg/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,galak/zephyr,Vudentz/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,galak/zephyr,finikorg/zephyr,nashif/zephyr,Vudentz/zephyr