kernfs: remove unneeded #if 0 guard

Commit f2eb478 ("kernfs: move struct kernfs_root out of the public
view.") moved kernfs_root out of kernfs.h, but my debugging code of a
 #if 0 was left in accidentally.  Fix that up by removing the guards.

Fixes: f2eb478 ("kernfs: move struct kernfs_root out of the public view.")
Cc: Tejun Heo <tj@kernel.org>
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Link: https://lore.kernel.org/r/20220318073452.1486568-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: gregkh

include/linux/kernfs.h

@@ -185,26 +185,6 @@ struct kernfs_syscall_ops {
 			 struct kernfs_root *root);
 };
 
-#if 0
-struct kernfs_root {
-	/* published fields */
-	struct kernfs_node	*kn;
-	unsigned int		flags;	/* KERNFS_ROOT_* flags */
-
-	/* private fields, do not use outside kernfs proper */
-	struct idr		ino_idr;
-	u32			last_id_lowbits;
-	u32			id_highbits;
-	struct kernfs_syscall_ops *syscall_ops;
-
-	/* list of kernfs_super_info of this root, protected by kernfs_rwsem */
-	struct list_head	supers;
-
-	wait_queue_head_t	deactivate_waitq;
-	struct rw_semaphore	kernfs_rwsem;
-};
-#endif
-
 struct kernfs_node *kernfs_root_to_node(struct kernfs_root *root);
 
 struct kernfs_open_file {