pc-bios/s390-ccw: Get rid of the the __u* types

pc-bios/s390-ccw: Get rid of the the __u* types

The types starting with double underscores have likely been
introduced into the s390-ccw bios to be able to re-use structs
from the Linux kernel in the past, but the corresponding structs
in cio.h have been changed there a long time ago already to not
use the variants with the double underscores anymore:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/diff/drivers/s390/cio/cio.h?id=cd6b4f27b9bb2a

So it would be good to replace these in the s390-ccw bios now, too.

Message-Id: <20230627114101.122231-1-thuth@redhat.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>