s390/zcrypt: CEX8S exploitation support

s390/zcrypt: CEX8S exploitation support

BugLink: https://bugs.launchpad.net/bugs/1959547
This patch adds CEX8 exploitation support for the AP bus code,
the zcrypt device driver zoo and the vfio device driver.

Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Reviewed-by: Jürgen Christ <jchrist@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
(cherry picked from commit 985214af939b9935dac94aa6fb56c85039fb77e8 linux-next)
Signed-off-by: Frank Heimes <frank.heimes@canonical.com>