Fixes following kernel build issue on ath79 with CONFIG_KERNEL_FTRACE=y
enabled:
Tracers (FTRACE) [Y/n/?] y
Kernel Function Tracer (FUNCTION_TRACER) [Y/n/?] y
Kernel Function Graph Tracer (FUNCTION_GRAPH_TRACER) [Y/n/?] y
Enable trace events for preempt and irq disable/enable (PREEMPTIRQ_EVENTS) [N/y/?] (NEW)
...
Preempt / IRQ disable delay thread to test latency tracers (PREEMPTIRQ_DELAY_TEST) [N/m/?] (NEW)
Signed-off-by: Petr Štetiar <ynezz@true.cz>
683341d98f