[Telink] Fix stale DTS on rebuild (project-chip#43235)

Author: s07641069

scripts/build/builders/telink.py

@@ -213,8 +213,7 @@ def get_cmd_prefixes(self):
         return cmd
 
     def generate(self):
-        if os.path.exists(self.output_dir):
-            return
+        os.makedirs(self.output_dir, exist_ok=True)
 
         flags = []
         if self.enable_ota: