Support for it was apparently never in the codebase, and the enum
value was recently removed from the public headers [1]

[1] https://aomedia.googlesource.com/aom/+/df4ffb73140fe31bebdabd17c1a7b53721e74838Signed-off-by: James Almer <jamrial@gmail.com>
Signed-off-by: Luca Barbato <lu_zero@gentoo.org>