drm/exynos: Fix freeing issues in exynos_drm_drv.c

Fixes the following errors:
drivers/gpu/drm/exynos/exynos_drm_drv.c:182 exynos_drm_open()
error: double free of 'file_priv'
drivers/gpu/drm/exynos/exynos_drm_drv.c:188 exynos_drm_open()
error: dereferencing freed memory 'file_priv'
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/exynos_drm_drv.c

@@ -171,21 +171,23 @@ static int exynos_drm_open(struct drm_device *dev, struct drm_file *file)
 	file->driver_priv = file_priv;
 
 	ret = exynos_drm_subdrv_open(dev, file);
-	if (ret) {
-		kfree(file_priv);
-		file->driver_priv = NULL;
-	}
+	if (ret)
+		goto out;
 
 	anon_filp = anon_inode_getfile("exynos_gem", &exynos_drm_gem_fops,
 					NULL, 0);
 	if (IS_ERR(anon_filp)) {
-		kfree(file_priv);
-		return PTR_ERR(anon_filp);
+		ret = PTR_ERR(anon_filp);
+		goto out;
 	}
 
 	anon_filp->f_mode = FMODE_READ | FMODE_WRITE;
 	file_priv->anon_filp = anon_filp;
 
+	return ret;
+out:
+	kfree(file_priv);
+	file->driver_priv = NULL;
 	return ret;
 }