Fix id3v1 tag spelling.
Revert "Fix id3v1 tag spelling."

The misspelling is used in the specification.

This reverts commit 95016fd1c8e1df5550d55eac1e3641970f7b38a0.
Add a comment about an intentional misspelling to the id3v1 tags.
lavfi/yadif: remove unused poll_frame callback
lavfi/yadif: fail during the configuration stage in case of invalid video size

This is better than repeatedly failing during the filtering stage.
lavfi/yadif: remove redundant NULL checks in uninit
lavfi/yadif: add support to named options and options introspection

Also rename the "enable_auto" field to "deint", to match the name of the
option.
lavfi/yadif: add support to named constants