The simh v3 UNIT structure only provided UNIT fields wait, u3, u4, u5 and u6
available for static initialization beyond what is provided by the UDATA
macro. This change assures that here as well.
If a simulator developer needs to initialize UNIT fields beyond what is
available here and via the UDATA macro, then explicit code usually in
the DEVICE reset routine should be used to initialize those fields.
Fix the CDC1700 simulator which statically initialized additional UNIT fields.