bpf: Remove unnecessary loop in task_file_seq_get_next()

After commit 0ede61d8 ("file: convert to SLAB_TYPESAFE_BY_RCU") this
loop always iterates exactly one time.  Delete the for statement and pull
the code in a tab.
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/ZoWJF51D4zWb6f5t@stanley.mountain

kernel/bpf/task_iter.c

@@ -261,6 +261,7 @@ task_file_seq_get_next(struct bpf_iter_seq_task_file_info *info)
 	u32 saved_tid = info->tid;
 	struct task_struct *curr_task;
 	unsigned int curr_fd = info->fd;
+	struct file *f;
 
 	/* If this function returns a non-NULL file object,
 	 * it held a reference to the task/file.
@@ -286,12 +287,8 @@ task_file_seq_get_next(struct bpf_iter_seq_task_file_info *info)
 	}
 
 	rcu_read_lock();
-	for (;; curr_fd++) {
-		struct file *f;
 	f = task_lookup_next_fdget_rcu(curr_task, &curr_fd);
-		if (!f)
-			break;
-
+	if (f) {
 		/* set info->fd */
 		info->fd = curr_fd;
 		rcu_read_unlock();