lsm: add comment block for security_sk_classify_flow LSM hook

security_sk_classify_flow LSM hook has no comment block. Add a comment
block with a brief description of LSM hook and its function parameters.
Signed-off-by: Khadija Kamran <kamrankhadijadj@gmail.com>
[PM: minor double-space fix]
Signed-off-by: Paul Moore <paul@paul-moore.com>

security/security.c

@@ -4421,6 +4421,13 @@ void security_sk_clone(const struct sock *sk, struct sock *newsk)
 }
 EXPORT_SYMBOL(security_sk_clone);
 
+/**
+ * security_sk_classify_flow() - Set a flow's secid based on socket
+ * @sk: original socket
+ * @flic: target flow
+ *
+ * Set the target flow's secid to socket's secid.
+ */
 void security_sk_classify_flow(struct sock *sk, struct flowi_common *flic)
 {
 	call_void_hook(sk_getsecid, sk, &flic->flowic_secid);