BKL: Remove BKL from OCFS2

The BKL in ocfs2/dlmfs is used in put_super, fill_super and remount_fs
that are all three protected by the superblocks s_umount rw_semaphore.

The use in ocfs2_control_open is evidently unrelated and the function
is protected by ocfs2_control_lock.

Therefore it is safe to remove the BKL entirely.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <joel.becker@oracle.com>