AML: Cannot interpret methods that contain FieldUnits

[newcomb-luke]

FieldUnit expansion is not yet implemented, and this causes method entries such as some _CRS methods and others to fail.
This causes this match branch to be called:

_ => Err(AmlError::TypeCannotBeWrittenToBufferField(value.type_of())),

This crashes, even though for some more simple methods, this should be able to be executed.