include/linux/frontswap.h: drop duplicated word in a comment

Drop the doubled word "in" in a comment.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Link: http://lkml.kernel.org/r/3af7ed91-ad62-8445-40a4-9e07a64b9523@infradead.orgSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/frontswap.h

@@ -10,7 +10,7 @@
 /*
  * Return code to denote that requested number of
  * frontswap pages are unused(moved to page cache).
- * Used in in shmem_unuse and try_to_unuse.
+ * Used in shmem_unuse and try_to_unuse.
  */
 #define FRONTSWAP_PAGES_UNUSED	2