media: Add AV1 uAPI

This patch adds the  AOMedia Video 1 (AV1) kernel uAPI.

This design is based on currently available AV1 API implementations and
aims to support the development of AV1 stateless video codecs
on Linux.

Signed-off-by: Daniel Almeida <daniel.almeida@collabora.com>
Co-developed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

Author: danielalmeida-collabora

Documentation/userspace-api/media/v4l/biblio.rst

@@ -427,3 +427,12 @@ VP9
 :title:     VP9 Bitstream & Decoding Process Specification
 
 :author:    Adrian Grange (Google), Peter de Rivaz (Argon Design), Jonathan Hunt (Argon Design)
+
+.. _av1:
+
+AV1
+===
+
+:title:     AV1 Bitstream & Decoding Process Specification
+
+:author:    Peter de Rivaz, Argon Design Ltd, Jack Haughton, Argon Design Ltd