drm/tegra: vic: Fix build warning when CONFIG_PM=n

drivers/gpu/drm/tegra/vic.c:326:12: error: ‘vic_runtime_suspend’ defined but not used [-Werror=unused-function]
 static int vic_runtime_suspend(struct device *dev)
            ^~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/tegra/vic.c:292:12: error: ‘vic_runtime_resume’ defined but not used [-Werror=unused-function]
 static int vic_runtime_resume(struct device *dev)
            ^~~~~~~~~~~~~~~~~~

Mark it as __maybe_unused.
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/drm/tegra/vic.c

@@ -323,7 +323,7 @@ static int vic_load_firmware(struct vic *vic)
 }
 
 
-static int vic_runtime_resume(struct device *dev)
+static int __maybe_unused vic_runtime_resume(struct device *dev)
 {
 	struct vic *vic = dev_get_drvdata(dev);
 	int err;
@@ -357,7 +357,7 @@ static int vic_runtime_resume(struct device *dev)
 	return err;
 }
 
-static int vic_runtime_suspend(struct device *dev)
+static int __maybe_unused vic_runtime_suspend(struct device *dev)
 {
 	struct vic *vic = dev_get_drvdata(dev);
 	int err;