Fix typos in /Documentation : 'U-Z'

This patch fixes typos in various Documentation txts. The patch addresses some
+words starting with the letters 'U-Z'.

Looks like I made it through the alphabet...just in time to start over again
+too!  Maybe I can fit more profound fixes into the next round...?  Time will
+tell. :)

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/robust-futex-ABI.txt b/Documentation/robust-futex-ABI.txt
index 8529a17..535f69f 100644
--- a/Documentation/robust-futex-ABI.txt
+++ b/Documentation/robust-futex-ABI.txt
@@ -170,7 +170,7 @@
  1) the 'head' pointer or an subsequent linked list pointer
     is not a valid address of a user space word
  2) the calculated location of the 'lock word' (address plus
-    'offset') is not the valud address of a 32 bit user space
+    'offset') is not the valid address of a 32 bit user space
     word
  3) if the list contains more than 1 million (subject to
     future kernel configuration changes) elements.