docs: load_config.py: ensure subdirs end with "/"

The logic with seeks for a subdir passed via SPHINXDIRS is
incomplete: if one uses something like:

	make SPHINXDIRS=arm pdfdocs

It will find both "arm" and "arm64" directories. Worse than
that, it will convert "arm64/index" to "4/index".
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

Documentation/sphinx/load_config.py

@@ -35,7 +35,7 @@ def loadConfig(namespace):
             latex_documents = namespace['latex_documents']
 
             for l in latex_documents:
-                if l[0].find(dir) == 0:
+                if l[0].find(dir + '/') == 0:
                     has = True
                     fn = l[0][len(dir) + 1:]
                     new_latex_docs.append((fn, l[1], l[2], l[3], l[4]))