s390/dasd: handle request magic consistently as unsigned int

Get rid of the rather odd casts to character pointer of the
dasd_ccw_req magic member and simply use the unsigned int value
unmodified everywhere.

Acked-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20211020115124.1735254-2-sth@linux.ibm.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>