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/ext4/ext4.h b/fs/ext4/ext4.h
index 3c20de1..df163da 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2455,7 +2455,7 @@
 BUFFER_FNS(Da_Mapped, da_mapped)
 
 /*
- * Add new method to test wether block and inode bitmaps are properly
+ * Add new method to test whether block and inode bitmaps are properly
  * initialized. With uninit_bg reading the block from disk is not enough
  * to mark the bitmap uptodate. We need to also zero-out the bitmap
  */