[S390] Get rid of a lot of sparse warnings.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/block/dasd_genhd.c b/drivers/s390/block/dasd_genhd.c
index d163632..47ba446 100644
--- a/drivers/s390/block/dasd_genhd.c
+++ b/drivers/s390/block/dasd_genhd.c
@@ -147,7 +147,7 @@
 	 */
 	memset(&bpart, 0, sizeof(struct blkpg_partition));
 	memset(&barg, 0, sizeof(struct blkpg_ioctl_arg));
-	barg.data = (void __user *) &bpart;
+	barg.data = (void __force __user *) &bpart;
 	barg.op = BLKPG_DEL_PARTITION;
 	for (bpart.pno = device->gdp->minors - 1; bpart.pno > 0; bpart.pno--)
 		ioctl_by_bdev(bdev, BLKPG, (unsigned long) &barg);