In KVM code we use masks to test/set control registers.

Let's define the ones we use in arch/s390/include/asm/ctl_reg.h and
replace all occurrences in KVM code.

As we will be needing the define for Clock-comparator sign control soon,
let's also add it.
Suggested-by: NCollin L. Walling <walling@linux.ibm.com>
Signed-off-by: NDavid Hildenbrand <david@redhat.com>
Reviewed-by: NCornelia Huck <cohuck@redhat.com>
Reviewed-by: NCollin Walling <walling@linux.ibm.com>
Acked-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: NJanosch Frank <frankja@linux.ibm.com>
Signed-off-by: NJanosch Frank <frankja@linux.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>