Fix simple typos

This corrects some trivial errors in ARM docs and comments,

Signed-off-by: Adrian Bunk <bunk@stusta.de>
diff --git a/Documentation/arm/Setup b/Documentation/arm/Setup
index 0abd072..0cb1e64 100644
--- a/Documentation/arm/Setup
+++ b/Documentation/arm/Setup
@@ -58,7 +58,7 @@
  video_y
 
    This describes the character position of cursor on VGA console, and
-   is otherwise unused. (should not used for other console types, and
+   is otherwise unused. (should not be used for other console types, and
    should not be used for other purposes).
 
  memc_control_reg