Fix cast stripping to match latest version of decomp

[xxk-i]

Very tiny fix. The room parser expects the elements of the .c RoomList to be prefixed with (u32)_... and the files themselves to be prefixed with a _. This is no longer the case in the mm decomp, the casts are now (uintptr_t) and the trailing _ is not in the filenames.

e.g.

RomFile Z2_CLOCKTOWERRoomList0x000164[] = {
    { (uintptr_t)_Z2_CLOCKTOWER_room_00SegmentRomStart, (uintptr_t)_Z2_CLOCKTOWER_room_00SegmentRomEnd },
};