drm/nouveau: Replace drm_dev_unref with drm_dev_put

This patch unifies the naming of DRM functions for reference counting
of struct drm_device. The resulting code is more aligned with the rest
of the Linux kernel interfaces.
Signed-off-by: Thomas Zimmermann <tdz@users.sourceforge.net>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nouveau_platform.c

@@ -36,7 +36,7 @@ static int nouveau_platform_probe(struct platform_device *pdev)
 
 	ret = drm_dev_register(drm, 0);
 	if (ret < 0) {
-		drm_dev_unref(drm);
+		drm_dev_put(drm);
 		return ret;
 	}