driverfs_remove_partitions(), devfs_register_partitions(),
driverfs_create_partitions(), devfs_register_partition(), devfs_register_disc(),
had lost 'minor' argument - it's always disk->first_minor these days.
disk_name() takes partition number instead of minor now.  Callers of
wipe_partitions() in fs/block_dev.c expanded.  Remaining caller passes
gendisk instead of kdev_t now.