enable CHECKPOINT_RESTORE on s390x
    
    Bugzilla:
      https://bugzilla.redhat.com/show_bug.cgi?id=1475719
      Fedora - Add new package CRIU for Docker on z Systems
    
    Koji: https://koji.fedoraproject.org/koji/taskinfo?taskID=20859205
    
    Testing:
     The kernel from koji was used to run the CRIU test suite (zdtm)
     on a RHEL s390x system. The kernel was started using kexec.
    
     # ./zdtm.py run  -a --keep-going
     [...]
     ################## ALL TEST(S) PASSED (TOTAL 317/SKIPPED 31) ###################
    
    Signed-off-by: Adrian Reber <adrian@lisas.de>