Documentation: Fix typo in multiple files in Documentation

Correct multiple spelling typo in Documentation.

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Rob Landley <rob@landley.net>
Reported-by: Anders Larsen <al@alarsen.net>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/Documentation/memory-hotplug.txt b/Documentation/memory-hotplug.txt
index 8f485d7..6d0c251 100644
--- a/Documentation/memory-hotplug.txt
+++ b/Documentation/memory-hotplug.txt
@@ -341,7 +341,7 @@
 --------------------------------
 8. Memory hotplug event notifier
 --------------------------------
-Memory hotplug has event notifer. There are 6 types of notification.
+Memory hotplug has event notifier. There are 6 types of notification.
 
 MEMORY_GOING_ONLINE
   Generated before new memory becomes available in order to be able to