tools/runqslower: Use __state instead of state

Commit 2f064a59a1 ("sched: Change task_struct::state") renamed task->state
to task->__state in task_struct. Fix runqslower to use the new name of the
field.

Fixes: 2f064a59a1 ("sched: Change task_struct::state")
Signed-off-by: SanjayKumar Jeyakumar <vjsanjay@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210707052914.21473-1-vjsanjay@gmail.com

tools/bpf/runqslower/runqslower.bpf.c

@@ -74,7 +74,7 @@ int handle__sched_switch(u64 *ctx)
 	u32 pid;
 
 	/* ivcsw: treat like an enqueue event and store timestamp */
-	if (prev->state == TASK_RUNNING)
+	if (prev->__state == TASK_RUNNING)
 		trace_enqueue(prev);
 
 	pid = next->pid;