website: Fixed broken links for mailing list subscriptions

Jira: https://gem5.atlassian.net/browse/GEM5-314
Change-Id: Ia4803b54c2f6a9a930455e3489dfff258904d468
diff --git a/_pages/mailing_list.md b/_pages/mailing_list.md
index 5a267b7..adf8dc0 100644
--- a/_pages/mailing_list.md
+++ b/_pages/mailing_list.md
@@ -6,11 +6,11 @@
 
 There are two mailing lists for gem5:
 
-* gem5-dev ([subscribe](http://www.gem5.org/mailman/listinfo/gem5-dev)) ---
+* gem5-dev ([subscribe](http://m5sim.org/mailman/listinfo/gem5-dev)) ---
 Discussions regarding gem5 development. Bug reports should be submitted to our
 [Jira Issue Tracker](https://gem5.atlassian.net), though the gem5-dev mailing
 list can be used to discuss bugs in greater detail.
-* gem5-users ([subscribe](http://www.gem5.org/mailman/listinfo/gem5-users)) ---
+* gem5-users ([subscribe](http://m5sim.org/mailman/listinfo/gem5-users)) ---
 General discussions about gem5 and its use.
 
 # Mail Archive