Add validate to components (#1631)

Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>

esphome/components/dfplayer/__init__.py

@@ -78,6 +78,12 @@ async def to_code(config):
         await automation.build_automation(trigger, [], conf)
 
 
+def validate(config, item_config):
+    uart.validate_device(
+        "dfplayer", config, item_config, baud_rate=9600, require_rx=False
+    )
+
+
 @automation.register_action(
     "dfplayer.play_next",
     NextAction,