coccinelle: api: remove kobj_to_dev.cocci script

Using kobj_to_dev() instead of container_of() is not universally
accepted among maintainers as an improvement. The warning leads to
repeated patch submissions that won't be accepted. Remove the script.

Cc: Christoph Hellwig <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Denis Efremov <[email protected]>
Cc: Julia Lawall <[email protected]>
Signed-off-by: Keith Busch <[email protected]>
Signed-off-by: Julia Lawall <[email protected]>
Acked-by: Jens Axboe <[email protected]>
Acked-by: Denis Efremov <[email protected]>