KVM: s390: gaccess: add ESOP2 handling

When we access guest memory and run into a protection exception, we
need to pass the exception data to the guest. ESOP2 provides detailed
information about all protection exceptions which ESOP1 only partially
provided.

The gaccess changes make sure, that the guest always gets all
available information.

Signed-off-by: Janosch Frank <frankja@linux.vnet.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>