spi: spi-fsl-qspi: use devm_spi_register_controller

The driver does not clearly unregister the spi controller.
Therefore calling an unbind and bind again will end up in a
Kernel crash.

The function devm_spi_register_controller will automatically
be unregister the SPI device.

Signed-off-by: Volker Haspel <volker.haspel@linutronix.de>
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-fsl-qspi.c

@@ -882,7 +882,7 @@ static int fsl_qspi_probe(struct platform_device *pdev)
 
 	ctlr->dev.of_node = np;
 
-	ret = spi_register_controller(ctlr);
+	ret = devm_spi_register_controller(dev, ctlr);
 	if (ret)
 		goto err_destroy_mutex;