[media] v4l: rcar_fdp1: mark PM functions as __maybe_unused

The new driver produces a warning when CONFIG_PM is disabled:

platform/rcar_fdp1.c:2408:12: error: 'fdp1_pm_runtime_resume' defined but not used [-Werror=unused-function]
platform/rcar_fdp1.c:2399:12: error: 'fdp1_pm_runtime_suspend' defined but not used [-Werror=unused-function]

This marks the two functions as __maybe_unused.

Fixes: 4710b752 ("[media] v4l: Add Renesas R-Car FDP1 Driver")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/platform/rcar_fdp1.c

@@ -2396,7 +2396,7 @@ static int fdp1_remove(struct platform_device *pdev)
 	return 0;
 }
 
-static int fdp1_pm_runtime_suspend(struct device *dev)
+static int __maybe_unused fdp1_pm_runtime_suspend(struct device *dev)
 {
 	struct fdp1_dev *fdp1 = dev_get_drvdata(dev);
 
@@ -2405,7 +2405,7 @@ static int fdp1_pm_runtime_suspend(struct device *dev)
 	return 0;
 }
 
-static int fdp1_pm_runtime_resume(struct device *dev)
+static int __maybe_unused fdp1_pm_runtime_resume(struct device *dev)
 {
 	struct fdp1_dev *fdp1 = dev_get_drvdata(dev);