Smack: compilation fix

On some build configurations PER_CLEAR_ON_SETID symbol was not
found when compiling smack_lsm.c. This patch fixes the issue by
explicitly doing #include <linux/personality.h>.
Signed-off-by: NJarkko Sakkinen <jarkko.j.sakkinen@gmail.com>
Signed-off-by: NCasey Schaufler <cschaufler@cschaufler-intel.(none)>

security/smack/smack_lsm.c

@@ -35,6 +35,7 @@
 #include <linux/audit.h>
 #include <linux/magic.h>
 #include <linux/dcache.h>
+#include <linux/personality.h>
 #include "smack.h"
 
 #define task_security(task)	(task_cred_xxx((task), security))