TTY: serial, cleanup atmel_set_ldisc

Current ldisc number is passed as a paramneter -- no need to dig it
out of the tty or ldisc. So switch PPS check to that.

No tty callback can be called with port->line higher than TTY driver
num. So remove the check.

This removes some port.tty users.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Viktar Palstsiuk <viktar.palstsiuk@promwad.com>
Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/tty/serial/atmel_serial.c

@@ -1256,12 +1256,7 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
 
 static void atmel_set_ldisc(struct uart_port *port, int new)
 {
-	int line = port->line;
-
-	if (line >= port->state->port.tty->driver->num)
-		return;
-
-	if (port->state->port.tty->ldisc->ops->num == N_PPS) {
+	if (new == N_PPS) {
 		port->flags |= UPF_HARDPPS_CD;
 		atmel_enable_ms(port);
 	} else {