sysfs, kernfs: remove cross inclusions of internal headers

fs/kernfs/kernfs-internal.h needed to include fs/sysfs/sysfs.h because
part of kernfs core implementation was living in sysfs.

fs/sysfs/sysfs.h needed to include fs/kernfs/kernfs-internal.h because
include/linux/kernfs.h didn't expose enough interface.

The separation is complete and neither is true anymore.  Remove the
cross inclusion and make sysfs a proper user of kernfs.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/kernfs/kernfs-internal.h

@@ -48,8 +48,6 @@ struct sysfs_addrm_cxt {
 	struct sysfs_dirent	*removed;
 };
 
-#include "../sysfs/sysfs.h"
-
 /*
  * mount.c
  */