treewide: Fix typos in various parts of the kernel, and fix some comments.

The below patch fixes some typos in various parts of the kernel, as well as fixes some comments.
Please let me know if I missed anything, and I will try to get it changed and resent.

Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 116ab67..c3308c3 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1943,7 +1943,7 @@
 };
 
 /*
- * This is called in transaction commmit time. If there are no orphan
+ * This is called in transaction commit time. If there are no orphan
  * files in the subvolume, it removes orphan item and frees block_rsv
  * structure.
  */