Fix typos in Documentation/: 'N'-'P'

This patch fixes typos in various Documentation txts. The patch addresses
some words starting with the letters 'N'-'P'.

Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
diff --git a/Documentation/lockdep-design.txt b/Documentation/lockdep-design.txt
index 2a76a4a..dab123d 100644
--- a/Documentation/lockdep-design.txt
+++ b/Documentation/lockdep-design.txt
@@ -170,7 +170,7 @@
 
 The validator achieves perfect, mathematical 'closure' (proof of locking
 correctness) in the sense that for every simple, standalone single-task
-locking sequence that occured at least once during the lifetime of the
+locking sequence that occurred at least once during the lifetime of the
 kernel, the validator proves it with a 100% certainty that no
 combination and timing of these locking sequences can cause any class of
 lock related deadlock. [*]