Improve field parsing: fixed-size fields may not have `bits` attribute
Improve field parsing: fixed-size fields may not have `bits` attribute

Some fields whose type imposes a fixed size may not find
useful a `bits` attribute.
For the sake of explaining, you cannot define a "bitfield float":
not only it makes no sense, but it's not possible to define it in
a C struct or in WSGD format.

alfateam123/lelei