docs-rst: conf.py: remove lscape from LaTeX preamble

Only the media book used this extension in the past, but
it is not required anymore.

Cleanup patch only.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/conf.py

@@ -273,9 +273,6 @@ latex_elements = {
     'preamble': '''
         \\usepackage{ifthen}
 
-        % Allow generate some pages in landscape
-        \\usepackage{lscape}
-
         % Put notes in color and let them be inside a table
 	\\definecolor{NoteColor}{RGB}{204,255,255}
 	\\definecolor{WarningColor}{RGB}{255,204,204}