spi: at91-usart: fix controller deregistration

commit 9acecc9 upstream.

Make sure to deregister the controller before disabling and releasing
underlying resources like clocks and DMA during driver unbind.

Fixes: e189254 ("spi: at91-usart: Add driver for at91-usart as SPI")
Cc: stable@vger.kernel.org	# 4.20
Cc: Radu Pirea <radu.pirea@microchip.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260409120419.388546-4-johan@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: jhovold

drivers/spi/spi-at91-usart.c

@@ -570,7 +570,7 @@ static int at91_usart_spi_probe(struct platform_device *pdev)
 	spin_lock_init(&aus->lock);
 	init_completion(&aus->xfer_completion);
 
-	ret = devm_spi_register_controller(&pdev->dev, controller);
+	ret = spi_register_controller(controller);
 	if (ret)
 		goto at91_usart_fail_register_controller;
 
@@ -648,8 +648,14 @@ static void at91_usart_spi_remove(struct platform_device *pdev)
 	struct spi_controller *ctlr = platform_get_drvdata(pdev);
 	struct at91_usart_spi *aus = spi_controller_get_devdata(ctlr);
 
+	spi_controller_get(ctlr);
+
+	spi_unregister_controller(ctlr);
+
 	at91_usart_spi_release_dma(ctlr);
 	clk_disable_unprepare(aus->clk);
+
+	spi_controller_put(ctlr);
 }
 
 static const struct dev_pm_ops at91_usart_spi_pm_ops = {