Add trace events for several s390 architecture specifics:

- SIE entry/exit
- common intercepts
- common instructions (sigp/diagnose)
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>