s390/sclp: convert list_for_each to entry variant

convert list_for_each() to list_for_each_entry() where
applicable.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zou Wei <zou_wei@huawei.com>
Link: https://lore.kernel.org/r/1623740220-15846-1-git-send-email-zou_wei@huawei.com
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

drivers/s390/char/sclp_tty.c

@@ -284,16 +284,14 @@ static int
 sclp_tty_chars_in_buffer(struct tty_struct *tty)
 {
 	unsigned long flags;
-	struct list_head *l;
 	struct sclp_buffer *t;
 	int count;
 
 	spin_lock_irqsave(&sclp_tty_lock, flags);
 	count = 0;
 	if (sclp_ttybuf != NULL)
 		count = sclp_chars_in_buffer(sclp_ttybuf);
-	list_for_each(l, &sclp_tty_outqueue) {
-		t = list_entry(l, struct sclp_buffer, list);
+	list_for_each_entry(t, &sclp_tty_outqueue, list) {
 		count += sclp_chars_in_buffer(t);
 	}
 	spin_unlock_irqrestore(&sclp_tty_lock, flags);