extmod/moductypes: addressof: Allow to take address of scalar struct field.
extmod/moductypes: addressof: Allow to take address of scalar struct field.

It's currently not possible to take an address of scalar field of a
structure, because expression like struct.field evaluates to field
value. So, allow a form uctypes.addressof(struct, "field").

pfalcon/micropython,pfalcon/micropython,pfalcon/micropython,pfalcon/micropython,pfalcon/micropython