Revert "serial: uartps: Do not allow use aliases >= MAX_UART_INSTANCES"

This reverts commit 2088cfd.

As Johan says, this driver needs a lot more work and these changes are
only going in the wrong direction:
  https://lkml.kernel.org/r/20190523091839.GC568@localhost

Reported-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/dac3898e3e32d963f357fb436ac9a7ac3cbcf933.1585905873.git.michal.simek@xilinx.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/xilinx_uartps.c

@@ -1712,8 +1712,7 @@ static int cdns_uart_probe(struct platform_device *pdev)
 	uart_unregister_driver(cdns_uart_data->cdns_uart_driver);
 err_out_id:
 	mutex_lock(&bitmap_lock);
-	if (cdns_uart_data->id < MAX_UART_INSTANCES)
-		clear_bit(cdns_uart_data->id, bitmap);
+	clear_bit(cdns_uart_data->id, bitmap);
 	mutex_unlock(&bitmap_lock);
 	return rc;
 }
@@ -1738,8 +1737,7 @@ static int cdns_uart_remove(struct platform_device *pdev)
 	rc = uart_remove_one_port(cdns_uart_data->cdns_uart_driver, port);
 	port->mapbase = 0;
 	mutex_lock(&bitmap_lock);
-	if (cdns_uart_data->id < MAX_UART_INSTANCES)
-		clear_bit(cdns_uart_data->id, bitmap);
+	clear_bit(cdns_uart_data->id, bitmap);
 	mutex_unlock(&bitmap_lock);
 	clk_disable_unprepare(cdns_uart_data->uartclk);
 	clk_disable_unprepare(cdns_uart_data->pclk);