tracing/hwlat: Drop the duplicate assignment in start_kthread()

We have set 'current_mask' to '&save_cpumask' in its declaration,
so there is no need to assign again.

Link: https://lkml.kernel.org/r/20200730082318.42584-1-haokexin@gmail.com

Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

kernel/trace/trace_hwlat.c

@@ -371,7 +371,6 @@ static int start_kthread(struct trace_array *tr)
 		return 0;
 
 	/* Just pick the first CPU on first iteration */
-	current_mask = &save_cpumask;
 	get_online_cpus();
 	cpumask_and(current_mask, cpu_online_mask, tracing_buffer_mask);
 	put_online_cpus();