xfs: fix various typos

Signed-off-by: Malcolm Parsons <malcolm.parsons@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
diff --git a/fs/xfs/xfs_btree.h b/fs/xfs/xfs_btree.h
index 789fffd..4f852b7 100644
--- a/fs/xfs/xfs_btree.h
+++ b/fs/xfs/xfs_btree.h
@@ -41,7 +41,7 @@
 /*
  * Generic btree header.
  *
- * This is a comination of the actual format used on disk for short and long
+ * This is a combination of the actual format used on disk for short and long
  * format btrees.  The first three fields are shared by both format, but
  * the pointers are different and should be used with care.
  *