Fixed wrapping of cell content in readthedocs style

The readthedocs style for sphinx has an issue where it does not auto
wrap text in table cells. This results in very long cells with a
vertical scrollbar.

This adds a css style sheet to fix this wrapping issue.

Signed-off-by: Claudius Heine <ch@denx.de>

docs/conf.py

@@ -251,6 +251,12 @@ html_static_path = ['_static']
 # Output file base name for HTML help builder.
 htmlhelp_basename = 'kasdoc'
 
+html_context = {
+    'extra_css_files': [
+        '_static/theme_overrides.css',  # override wide tables in RTD theme
+     ],
+}
+
 # -- Options for LaTeX output ---------------------------------------------
 
 latex_elements = {