sysfs: move struct sysfs_dirent to private header

struct sysfs_dirent is private to the fs/sysfs/ subtree.  It is
not even referenced as an opaque structure outside of that subtree.

The following patch moves the declaration from include/linux/sysfs.h to
fs/sysfs/sysfs.h, making it clearer that nothing else in the kernel
dereferences it.

I have been running this patch for years.  Please integrate and forward
upstream if there are no objections.

From: "Adam J. Richter" <adam@yggdrasil.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index d976b00..a77c57e 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -1,3 +1,14 @@
+struct sysfs_dirent {
+	atomic_t		s_count;
+	struct list_head	s_sibling;
+	struct list_head	s_children;
+	void 			* s_element;
+	int			s_type;
+	umode_t			s_mode;
+	struct dentry		* s_dentry;
+	struct iattr		* s_iattr;
+	atomic_t		s_event;
+};
 
 extern struct vfsmount * sysfs_mount;
 extern struct kmem_cache *sysfs_dir_cachep;