net: lwm2m: default stack size with SenML CBOR
net: lwm2m: default stack size with SenML CBOR

SenML CBOR data is stored statically in RAM and does not use process
stack.

Signed-off-by: Veijo Pesonen <cb89a3750227d52d34160f03c031368aef19d3be@nordicsemi.no>

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