netlabel: Deletion of an unnecessary check before the function call "cipso_v4_doi_free"

The cipso_v4_doi_free() function tests whether its argument is NULL and then
returns immediately. Thus the test around the call is not needed.

This issue was detected by using the Coccinelle software.
Signed-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Acked-by: NPaul Moore <paul@paul-moore.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/netlabel/netlabel_cipso_v4.c

@@ -324,8 +324,7 @@ static int netlbl_cipsov4_add_std(struct genl_info *info,
 	return 0;
 
 add_std_failure:
-	if (doi_def)
-		cipso_v4_doi_free(doi_def);
+	cipso_v4_doi_free(doi_def);
 	return ret_val;
 }