s390x/ioinst: set type and len for SEI response

If no event information is pending, the return code
is set to 0x0005 and the length of the response is
set to 8 bytes.

Signed-off-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Song Shan Gong <gongss@linux.vnet.ibm.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>

target-s390x/ioinst.c

@@ -616,7 +616,8 @@ static void ioinst_handle_chsc_sei(ChscReq *req, ChscResp *res)
             (*res_flags) &= ~0x80;
         }
     } else {
-        res->code = cpu_to_be16(0x0004);
+        res->code = cpu_to_be16(0x0005);
+        res->len = cpu_to_be16(CHSC_MIN_RESP_LEN);
     }
 }