Fix misspellings of "whether" in comments.

"Whether" is misspelled in various comments across the tree; this
fixes them. No code changes.

Signed-off-by: Adam Buchbinder <adam.buchbinder@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/fs/btrfs/ordered-data.h b/fs/btrfs/ordered-data.h
index dd27a0b..853fc7b 100644
--- a/fs/btrfs/ordered-data.h
+++ b/fs/btrfs/ordered-data.h
@@ -76,7 +76,7 @@
 
 #define BTRFS_ORDERED_IOERR 6 /* We had an io error when writing this out */
 
-#define BTRFS_ORDERED_UPDATED_ISIZE 7 /* indicates wether this ordered extent
+#define BTRFS_ORDERED_UPDATED_ISIZE 7 /* indicates whether this ordered extent
 				       * has done its due diligence in updating
 				       * the isize. */