s390/dasd: Use scnprintf() instead of sprintf()

s390/dasd: Use scnprintf() instead of sprintf()

Use scnprintf() instead of sprintf() for those cases where the
destination is an array and the size of the array is known at compile
time.

This prevents theoretical buffer overflows, but also avoids that people
again and again spend time to figure out if the code is actually safe.

Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>