scripts: sphinx-build-wrapper: get rid of uapi/media Makefile

scripts: sphinx-build-wrapper: get rid of uapi/media Makefile

Now that kernel-include directive supports parsing data
structs directly, we can finally get rid of the horrible hack
we added to support parsing media uAPI symbols.

As a side effect, Documentation/output doesn't have anymore
media auto-generated .rst files on it.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/5dbb257a4b283697271c9c7b8f4713857e8191c8.1755872208.git.mchehab+huawei@kernel.org