spi: cadence: use to_platform_device()

Use to_platform_device() instead of open-coding it.
Signed-off-by: Geliang Tang <geliangtang@163.com>
Reviewed-by: Moritz Fischer <moritz.fischer@ettus.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-cadence.c

@@ -617,8 +617,7 @@ static int cdns_spi_remove(struct platform_device *pdev)
  */
 static int __maybe_unused cdns_spi_suspend(struct device *dev)
 {
-	struct platform_device *pdev = container_of(dev,
-			struct platform_device, dev);
+	struct platform_device *pdev = to_platform_device(dev);
 	struct spi_master *master = platform_get_drvdata(pdev);
 	struct cdns_spi *xspi = spi_master_get_devdata(master);
 
@@ -641,8 +640,7 @@ static int __maybe_unused cdns_spi_suspend(struct device *dev)
  */
 static int __maybe_unused cdns_spi_resume(struct device *dev)
 {
-	struct platform_device *pdev = container_of(dev,
-			struct platform_device, dev);
+	struct platform_device *pdev = to_platform_device(dev);
 	struct spi_master *master = platform_get_drvdata(pdev);
 	struct cdns_spi *xspi = spi_master_get_devdata(master);
 	int ret = 0;