s390x: Create QOM device for s390 storage keys

A new QOM style device is provided to back guest storage keys. A special
version for KVM is created, which handles the storage key access via
KVM_S390_GET_SKEYS and KVM_S390_SET_SKEYS ioctl.

Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Jason J. Herne <jjherne@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
diff --git a/MAINTAINERS b/MAINTAINERS
index 08f356a..5a4bac8 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -569,6 +569,7 @@
 F: hw/s390x/sclp*.[hc]
 F: hw/s390x/ipl*.[hc]
 F: hw/s390x/*pci*.[hc]
+F: hw/s390x/s390-skeys*.c
 F: include/hw/s390x/
 F: pc-bios/s390-ccw/
 T: git git://github.com/cohuck/qemu virtio-ccw-upstr