docs: temporarily disable the kernel-doc extension

Preserve bisectability while we update scripts/kernel-doc from Linux.
Without this patch, building with Sphinx 3 would break while we
revert our own Sphinx 3 support and replace it with Linux's.

Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
1 file changed