KVM: s390: generate facility mask from readable list

Automatically generate the KVM facility mask out of a readable list.
Manually changing the masks is very error prone, especially if the
special IBM bit numbering has to be considered.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>