super-intel: don't mark structs 'packed' unnecessarily
super-intel marks a number of structures 'packed', but this
doesn't change the layout - they are already well organized.
This is a problem a gcc warns when code takes the address
of a field in a packet struct - as super-intel sometimes does.
So remove the marking where isn't needed.
Do ensure this does introduce a regression, add a compile-time
assertion that the size of the structure is exactly the value
it had before the 'packed' notation was removed.
Note that a couple of structure do need to be packed.
As the address of fields is never taken, that is safe.