serial: core: Colocate crucial structure linkage

The key function of uart_add_one_port() is to cross-reference the
UART driver's port structure with the serial core's state table;
keep the assignments together and document this crucial association.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/serial_core.c

@@ -2590,11 +2590,12 @@ int uart_add_one_port(struct uart_driver *drv, struct uart_port *uport)
 		goto out;
 	}
 
+	/* Link the port to the driver state table and vice versa */
 	state->uart_port = uport;
-	state->pm_state = UART_PM_STATE_UNDEFINED;
+	uport->state = state;
 
+	state->pm_state = UART_PM_STATE_UNDEFINED;
 	uport->cons = drv->cons;
-	uport->state = state;
 
 	/*
 	 * If this port is a console, then the spinlock is already