ps3vram: add error handling support for add_disk()

We never checked for errors on add_disk() as this function
returned void. Now that this is fixed, use the shiny new
error handling.

Signed-off-by: Luis Chamberlain <[e-mail]>
Acked-by: Geoff Levand <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jens Axboe <[e-mail]>

drivers/block/ps3vram.c

···
 	dev_info(&dev->core, "%s: Using %llu MiB of GPU memory\n",
 		 gendisk->disk_name, get_capacity(gendisk) >> 11);
 
-	device_add_disk(&dev->core, gendisk, NULL);
+	error = device_add_disk(&dev->core, gendisk, NULL);
+	if (error)
+		goto out_cleanup_disk;
+
 	return 0;
 
+out_cleanup_disk:
+	blk_cleanup_disk(gendisk);
 out_cache_cleanup:
 	remove_proc_entry(DEVICE_NAME, NULL);
 	ps3vram_cache_cleanup(dev);