tty: xtensa/iss, setup the timer statically

Use DEFINE_TIMER and avoid runtime initialization of the serial_timer.

Cc: Chris Zankel <chris@zankel.net>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: linux-xtensa@linux-xtensa.org
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210302062214.29627-32-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/xtensa/platforms/iss/console.c

@@ -31,21 +31,18 @@
 #define SERIAL_MAX_NUM_LINES 1
 #define SERIAL_TIMER_VALUE (HZ / 10)
 
+static void rs_poll(struct timer_list *);
+
 static struct tty_driver *serial_driver;
 static struct tty_port serial_port;
-static struct timer_list serial_timer;
-
+static DEFINE_TIMER(serial_timer, rs_poll);
 static DEFINE_SPINLOCK(timer_lock);
 
-static void rs_poll(struct timer_list *);
-
 static int rs_open(struct tty_struct *tty, struct file * filp)
 {
 	spin_lock_bh(&timer_lock);
-	if (tty->count == 1) {
-		timer_setup(&serial_timer, rs_poll, 0);
+	if (tty->count == 1)
 		mod_timer(&serial_timer, jiffies + SERIAL_TIMER_VALUE);
-	}
 	spin_unlock_bh(&timer_lock);
 
 	return 0;