INTRNG - redefine struct intr_map_data to avoid headers pollution. Each
struct associated with some type defined in enum intr_map_data_type
must have struct intr_map_data on the top of its own definition now.
When such structs are used, correct type and size must be filled in.

There are three such structs defined in sys/intr.h now. Their
definitions should be moved to corresponding headers by follow-up
commits.

While this change was propagated to all INTRNG like PICs,
pic_map_intr() method implementations were corrected on some places.
For this specific method, it's ensured by a caller that the 'data'
argument passed to this method is never NULL. Also, the return error
values were standardized there.