Doc: Change wikipedia's URL from http to https

Recently wikipedia announced to secure access to the servers.
Now all http access re-route to https.

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
diff --git a/Documentation/RCU/RTFP.txt b/Documentation/RCU/RTFP.txt
index f29bcbc..370ca00 100644
--- a/Documentation/RCU/RTFP.txt
+++ b/Documentation/RCU/RTFP.txt
@@ -1496,7 +1496,7 @@
 ,month="July"
 ,day="8"
 ,year="2006"
-,note="\url{http://en.wikipedia.org/wiki/Read-copy-update}"
+,note="\url{https://en.wikipedia.org/wiki/Read-copy-update}"
 ,annotation={
 	Wikipedia RCU page as of July 8 2006.
 	[Viewed August 21, 2006]