staging: fwserial: fix TIOCSSERIAL jiffies conversions

The port close_delay parameter set by TIOCSSERIAL is specified in
jiffies, while the value returned by TIOCGSERIAL is specified in
centiseconds.

Add the missing conversions so that TIOCGSERIAL works as expected also
when HZ is not 100.

Fixes: 7355ba3445 ("staging: fwserial: Add TTY-over-Firewire serial driver")
Cc: stable@vger.kernel.org      # 3.8
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210407102334.32361-2-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/fwserial/fwserial.c

@@ -1223,7 +1223,7 @@ static int get_serial_info(struct tty_struct *tty,
 	ss->flags = port->port.flags;
 	ss->xmit_fifo_size = FWTTY_PORT_TXFIFO_LEN;
 	ss->baud_base = 400000000;
-	ss->close_delay = port->port.close_delay;
+	ss->close_delay = jiffies_to_msecs(port->port.close_delay) / 10;
 	mutex_unlock(&port->port.mutex);
 	return 0;
 }
@@ -1245,7 +1245,7 @@ static int set_serial_info(struct tty_struct *tty,
 			return -EPERM;
 		}
 	}
-	port->port.close_delay = ss->close_delay * HZ / 100;
+	port->port.close_delay = msecs_to_jiffies(ss->close_delay * 10);
 	mutex_unlock(&port->port.mutex);
 
 	return 0;