parser yang BUGFIX extension instance statement order

Fixes #1753
diff --git a/src/parser_yang.c b/src/parser_yang.c
index 692064b..41e1acd 100644
--- a/src/parser_yang.c
+++ b/src/parser_yang.c
@@ -4180,9 +4180,11 @@
         case LY_STMT_RPC:
         case LY_STMT_TYPEDEF:
         case LY_STMT_USES:
-        case LY_STMT_EXTENSION_INSTANCE:
             mod_stmt = Y_MOD_BODY;
             break;
+        case LY_STMT_EXTENSION_INSTANCE:
+            /* no place in the statement order defined */
+            break;
         default:
             /* error handled in the next switch */
             break;
@@ -4386,9 +4388,11 @@
         case LY_STMT_RPC:
         case LY_STMT_TYPEDEF:
         case LY_STMT_USES:
-        case LY_STMT_EXTENSION_INSTANCE:
             mod_stmt = Y_MOD_BODY;
             break;
+        case LY_STMT_EXTENSION_INSTANCE:
+            /* no place in the statement order defined */
+            break;
         default:
             /* error handled in the next switch */
             break;