The quirky behavior when accessing of 0x0 address is related to exact ARC SoCs/boards and not to entire ARC EM CPUs family. So check for exact SoCs configs (CONFIG_SOC_ARC_IOT and CONFIG_SOC_NSIM) instead of checking against CONFIG_CPU_ARCEM. Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>