As reported by Vipul Gandhi, the current serial_match_port() doesn't work 
for tty-devices using dynamic major number allocation. Fix it.

Signed-off-by: Guennadi Liakhovetski <redacted>
Tested-by: Vipul Gandhi <redacted>

---

diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index 0f5a179..593ae85 100644
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c

@@ -1949,7 +1949,9 @@ struct uart_match {
 static int serial_match_port(struct device *dev, void *data)
 {
 	struct uart_match *match = data;
-	dev_t devt = MKDEV(match->driver->major, match->driver->minor) + match->port->line;
+	struct tty_driver *tty_drv = match->driver->tty_driver;
+	dev_t devt = MKDEV(tty_drv->major, tty_drv->minor_start) +
+		match->port->line;
 
 	return dev->devt == devt; /* Actually, only one tty per port */