s390/cio: use while (i--) pattern to clean up

Use more natural while (i--) pattern to clean up allocated resources.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Link: https://lore.kernel.org/r/20240222134501.236871-1-andriy.shevchenko@linux.intel.com


Signed-off-by: Heiko Carstens <hca@linux.ibm.com>