[Fix] Add (in)equality operator for POD types

POD types (before this change) didn't include equality operators,
so using them as a rep property would fail for SimpleSource, since
the auto-generated setter had "if (x != _x)" as a check.

Change-Id: I07cc8fc212a6a0206830f140fbb4bfc6d5cba137
Reviewed-by: Continuous Integration (KDAB) <build@kdab.com>
Reviewed-by: Kevin Funk <kevin.funk@kdab.com>
Reviewed-by: BogDan Vatra <bogdan@kdab.com>