spi/tegra: Fix device remove function

The call to spi_unregister_master() in the device remove function frees device
memory, and with it any device local data. However, device local data is still
accessed after the call to spi_unregister_master().

Acquire a reference to the SPI master device and release it after cleanup is
complete to solve the problem.
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

drivers/spi/spi-tegra.c

@@ -652,7 +652,7 @@ static int __devexit spi_tegra_remove(struct platform_device *pdev)
 	struct spi_tegra_data	*tspi;
 	struct resource		*r;
 
-	master = dev_get_drvdata(&pdev->dev);
+	master = spi_master_get(dev_get_drvdata(&pdev->dev));
 	tspi = spi_master_get_devdata(master);
 
 	spi_unregister_master(master);
@@ -668,6 +668,8 @@ static int __devexit spi_tegra_remove(struct platform_device *pdev)
 	clk_put(tspi->clk);
 	iounmap(tspi->base);
 
+	spi_master_put(master);
+
 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	release_mem_region(r->start, resource_size(r));