Revert "doc: update Kernel documentation build system"

Unfortunately we now see a number of now-fatal warnings about duplicate
labels.  It is often unclear how best to re-write the document in
question to not duplicate these otherwise logical headings.

This reverts commit 10a1df3cd43ba2fe893d5dd1aeb2e7109ef0007f.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/doc/sphinx/kernellog.py b/doc/sphinx/kernellog.py
index 8ac7d27..af924f5 100644
--- a/doc/sphinx/kernellog.py
+++ b/doc/sphinx/kernellog.py
@@ -25,8 +25,4 @@
     else:
         app.verbose(message)
 
-def info(app, message):
-    if UseLogging:
-        logger.info(message)
-    else:
-        app.info(message)
+