Fix simple typos

This corrects some trivial errors in ARM docs and comments,

Signed-off-by: Adrian Bunk <[e-mail]>

Documentation/arm/Booting

···
 
 In either case, the following conditions must be met:
 
-- Quiesce all DMA capable devicess so that memory does not get
+- Quiesce all DMA capable devices so that memory does not get
   corrupted by bogus network packets or disk data. This will save
   you many hours of debug.
 

Documentation/arm/README

···
   Although modularisation is supported (and required for the FP emulator),
   each module on an ARM2/ARM250/ARM3 machine when is loaded will take
   memory up to the next 32k boundary due to the size of the pages.
-  Therefore, modularisation on these machines really worth it?
+  Therefore, is modularisation on these machines really worth it?
 
   However, ARM6 and up machines allow modules to take multiples of 4k, and
   as such Acorn RiscPCs and other architectures using these processors can

Documentation/arm/Setup

···
  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

include/linux/timer.h

···
  * @timer: the timer to be added
  *
  * The kernel will do a ->function(->data) callback from the
- * timer interrupt at the ->expired point in the future. The
+ * timer interrupt at the ->expires point in the future. The
  * current time is 'jiffies'.
  *
- * The timer's ->expired, ->function (and if the handler uses it, ->data)
+ * The timer's ->expires, ->function (and if the handler uses it, ->data)
  * fields must be set prior calling this function.
  *
- * Timers with an ->expired field in the past will be executed in the next
+ * Timers with an ->expires field in the past will be executed in the next
  * timer tick.
  */
 static inline void add_timer(struct timer_list *timer)