drm/msm/mdp5: mark runtime_pm functions as __maybe_unused

When CONFIG_PM is disabled, we get harmless warnings about unused
functions:

drivers/gpu/drm/msm/mdp/mdp5/mdp5_kms.c:1025:12: error: 'mdp5_runtime_resume' defined but not used [-Werror=unused-function]
 static int mdp5_runtime_resume(struct device *dev)
            ^~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/msm/mdp/mdp5/mdp5_kms.c:1015:12: error: 'mdp5_runtime_suspend' defined but not used [-Werror=unused-function]
 static int mdp5_runtime_suspend(struct device *dev)
            ^~~~~~~~~~~~~~~~~~~~

This marks both functions as __maybe_unused so the compiler
can drop them silently.

Fixes: d68fe15b1878 ("drm/msm/mdp5: Use runtime PM get/put API instead of toggling clocks")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rob Clark <robdclark@gmail.com>

drivers/gpu/drm/msm/mdp/mdp5/mdp5_kms.c

@@ -1012,7 +1012,7 @@ static int mdp5_dev_remove(struct platform_device *pdev)
 	return 0;
 }
 
-static int mdp5_runtime_suspend(struct device *dev)
+static __maybe_unused int mdp5_runtime_suspend(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct mdp5_kms *mdp5_kms = platform_get_drvdata(pdev);
@@ -1022,7 +1022,7 @@ static int mdp5_runtime_suspend(struct device *dev)
 	return mdp5_disable(mdp5_kms);
 }
 
-static int mdp5_runtime_resume(struct device *dev)
+static __maybe_unused int mdp5_runtime_resume(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct mdp5_kms *mdp5_kms = platform_get_drvdata(pdev);