The IBM partition parser requires device type specific information only
available to the DASD driver to correctly register partitions. The
current approach of using ioctl_by_bdev with a fake user space pointer
is discouraged.

Fix this by replacing IOCTL calls with direct in-kernel function calls.
Suggested-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NStefan Haberland <sth@linux.ibm.com>
Reviewed-by: NJan Hoeppner <hoeppner@linux.ibm.com>
Reviewed-by: NPeter Oberparleiter <oberpar@linux.ibm.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>