s390/cio: simplify the calculation of variables

Fix the following coccicheck warnings:
./arch/s390/include/asm/scsw.h:695:47-49: WARNING
 !A || A && B is equivalent to !A || B

I apply a readable version just to get rid of a warning.

Signed-off-by: Haowen Bai <baihaowen@meizu.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Link: https://lore.kernel.org/r/1649297808-5048-1-git-send-email-baihaowen@meizu.com


Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>