audit: do not cast audit_rule_data pointers pointlesly

For some sort of legacy support audit_rule is a subset of (and first
entry in) audit_rule_data.  We don't actually need or use audit_rule.
We just do a cast from one to the other for no gain what so ever.  Stop
the crazy casting.
Signed-off-by: Eric Paris <eparis@redhat.com>

kernel/auditfilter.c

@@ -228,7 +228,7 @@ static int audit_match_signal(struct audit_entry *entry)
 #endif
 
 /* Common user-space to kernel rule translation. */
-static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule)
+static inline struct audit_entry *audit_to_entry_common(struct audit_rule_data *rule)
 {
 	unsigned listnr;
 	struct audit_entry *entry;
@@ -405,7 +405,7 @@ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
 	int i;
 	char *str;
 
-	entry = audit_to_entry_common((struct audit_rule *)data);
+	entry = audit_to_entry_common(data);
 	if (IS_ERR(entry))
 		goto exit_nofree;