nacm BUGFIX relax check for the parent statements

Specification says that in case the extension is not instantiated in
data node, it is supposed to be ignored. So far, libyang was generating
error, so this patch changes it to warning and ignores the extension.
diff --git a/src/plugins_exts_nacm.c b/src/plugins_exts_nacm.c
index 8589bce..9981e5f 100644
--- a/src/plugins_exts_nacm.c
+++ b/src/plugins_exts_nacm.c
@@ -93,9 +93,9 @@
 
     /* check that the extension is instantiated at an allowed place - data node */
     if (c_ext->parent_type != LYEXT_PAR_NODE) {
-        lyext_log(c_ext, LY_LLERR, LY_EVALID, cctx->path, "Extension %s is allowed only in a data nodes, but it is placed in \"%s\" statement.",
+        lyext_log(c_ext, LY_LLWRN, 0, cctx->path, "Extension %s is allowed only in a data nodes, but it is placed in \"%s\" statement.",
                 p_ext->name, lyext_parent2str(c_ext->parent_type));
-        return LY_EVALID;
+        return LY_ENOT;
     } else {
         parent = (struct lysc_node *)c_ext->parent;
         if (!(parent->nodetype & (LYS_CONTAINER | LYS_LEAF | LYS_LEAFLIST | LYS_LIST | LYS_CHOICE | LYS_ANYDATA |
@@ -103,9 +103,9 @@
             /* note LYS_AUGMENT and LYS_USES is not in the list since they are not present in the compiled tree. Instead, libyang
              * passes all their extensions to their children nodes */
 invalid_parent:
-            lyext_log(c_ext, LY_LLERR, LY_EVALID, cctx->path,
+            lyext_log(c_ext, LY_LLWRN, 0, cctx->path,
                     "Extension %s is not allowed in %s statement.", p_ext->name, lys_nodetype2str(parent->nodetype));
-            return LY_EVALID;
+            return LY_ENOT;
         }
         if ((c_ext->data == (void *)&nacm_deny_write) && (parent->nodetype & (LYS_RPC | LYS_ACTION | LYS_NOTIF))) {
             goto invalid_parent;