docs-rst: Don't mangle with UTF-8 chars on LaTeX/PDF output

pdflatex doesn't accept using some UTF-8 chars, like
"equal or less than" or "equal or greater than" chars. However,
the media documents use them. So, we need to use XeLaTeX for
conversion, and a font that accepts such characters.

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

Documentation/conf.py

@@ -254,6 +254,10 @@ latex_elements = {
 # Latex figure (float) alignment
 #'figure_align': 'htbp',
 
+# Don't mangle with UTF-8 chars
+'inputenc': '',
+'utf8extra': '',
+
 # Additional stuff for the LaTeX preamble.
     'preamble': '''
         % Allow generate some pages in landscape
@@ -281,6 +285,13 @@ latex_elements = {
           \\end{graybox}
         }
 	\\makeatother
+
+	% Use some font with UTF-8 support with XeLaTeX
+        \\usepackage{fontspec}
+        \\setsansfont{DejaVu Serif}
+        \\setromanfont{DejaVu Sans}
+        \\setmonofont{DejaVu Sans Mono}
+
      '''
 }