coccinelle: free: add version constraint

The various functions contain a NULL check starting in v5.15.
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>

scripts/coccinelle/free/ifnulldev_put.cocci

@@ -7,6 +7,7 @@
 // Copyright: (C) 2022 Ziyang Xuan.
 // Comments: -
 // Options: --no-includes --include-headers
+// Version min: 5.15
 
 virtual patch
 virtual org