KVM: s390: Fix RRBE return code not being CC

reset_guest_reference_bit needs to return the CC, so we can set it in
the guest PSW when emulating RRBE. Right now it only returns 0.

Let's fix that.
Signed-off-by: Janosch Frank <frankja@linux.vnet.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

arch/s390/mm/pgtable.c

@@ -741,7 +741,7 @@ int reset_guest_reference_bit(struct mm_struct *mm, unsigned long addr)
 
 	pgste_set_unlock(ptep, new);
 	pte_unmap_unlock(ptep, ptl);
-	return 0;
+	return cc;
 }
 EXPORT_SYMBOL(reset_guest_reference_bit);