serial: pass state to __uart_start() directly

__uart_start() does not need a tty struct. It works only with
uart_state. So pass the latter directly.

Signed-off-by: Jiri Slaby (SUSE) <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/tty/serial/serial_core.c

···
 	uart_port_unlock(port, flags);
 }
 
-static void __uart_start(struct tty_struct *tty)
+static void __uart_start(struct uart_state *state)
 {
-	struct uart_state *state = tty->driver_data;
 	struct uart_port *port = state->uart_port;
 	struct serial_port_device *port_dev;
 	int err;
···
 	unsigned long flags;
 
 	port = uart_port_lock(state, flags);
-	__uart_start(tty);
+	__uart_start(state);
 	uart_port_unlock(port, flags);
 }
 
···
 		if (!old_hw_stopped)
 			uport->ops->stop_tx(uport);
 		else
-			__uart_start(tty);
+			__uart_start(state);
 	}
 	spin_unlock_irq(&uport->lock);
 }
···
 		ret += c;
 	}
 
-	__uart_start(tty);
+	__uart_start(state);
 	uart_port_unlock(port, flags);
 	return ret;
 }