smack: remove redundant structure variable from header.

commit afb1cbe3 ("LSM: Infrastructure management
of the inode security") removed usage of smk_rcu,
thus removing it from structure.
Signed-off-by: Maninder Singh <maninder1.s@samsung.com>
Signed-off-by: Vaneet Narang <v.narang@samsung.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>

security/smack/smack.h

@@ -111,7 +111,6 @@ struct inode_smack {
 	struct smack_known	*smk_mmap;	/* label of the mmap domain */
 	struct mutex		smk_lock;	/* initialization lock */
 	int			smk_flags;	/* smack inode flags */
-	struct rcu_head         smk_rcu;	/* for freeing inode_smack */
 };
 
 struct task_smack {