serial/aspeed-vuart: fix a couple mod_timer() calls

The "unthrottle_timeout" is HZ/10 but mod_timer() takes a the actual
jiffie where you want it to timeout, not an offset.

Fixes: 5909c0bf ("serial/aspeed-vuart: Implement quick throttle mechanism")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_aspeed_vuart.c

@@ -226,7 +226,8 @@ static void aspeed_vuart_unthrottle_exp(struct timer_list *timer)
 	struct uart_8250_port *up = vuart->port;
 
 	if (!tty_buffer_space_avail(&up->port.state->port)) {
-		mod_timer(&vuart->unthrottle_timer, unthrottle_timeout);
+		mod_timer(&vuart->unthrottle_timer,
+			  jiffies + unthrottle_timeout);
 		return;
 	}
 
@@ -271,7 +272,7 @@ static int aspeed_vuart_handle_irq(struct uart_port *port)
 			if (!timer_pending(&vuart->unthrottle_timer)) {
 				vuart->port = up;
 				mod_timer(&vuart->unthrottle_timer,
-						unthrottle_timeout);
+					  jiffies + unthrottle_timeout);
 			}
 
 		} else {