gfio: add option group/category to filename_format

Signed-off-by: Jens Axboe <axboe@kernel.dk>
parse: catch all options without a group/category set

Signed-off-by: Jens Axboe <axboe@kernel.dk>
parse: set invalid group on option with no group set

Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add group/category to numa/mem node options

Signed-off-by: Jens Axboe <axboe@kernel.dk>