docs: Fix conf.py for Sphinx 2.0

commit 3bc8088464712fdcb078eefb68837ccfcc413c88 upstream.

Our version check in Documentation/conf.py never envisioned a world where
Sphinx moved beyond 1.x.  Now that the unthinkable has happened, fix our
version check to handle higher version numbers correctly.
Signed-off-by: NJonathan Corbet <corbet@lwn.net>
[rebase for u-boot]
Signed-off-by: NSean Anderson <seanga2@gmail.com>

doc/conf.py

@@ -37,7 +37,7 @@ needs_sphinx = '1.3'
 extensions = ['kerneldoc', 'rstFlatTable', 'kernel_include', 'cdomain', 'kfigure']
 
 # The name of the math extension changed on Sphinx 1.4
-if major == 1 and minor > 3:
+if (major == 1 and minor > 3) or (major > 1):
     extensions.append("sphinx.ext.imgmath")
 else:
     extensions.append("sphinx.ext.pngmath")