Merge branch 'dfplayer_batch_read' into integration

esphome/components/dfplayer/dfplayer.cpp

@@ -132,13 +132,8 @@ void DFPlayer::send_cmd_(uint8_t cmd, uint16_t argument) {
 }
 
 void DFPlayer::loop() {
-  // Read message
-  // All current UART available() implementations return >= 0,
-  // use <= 0 to future-proof against any that may return negative on error.
+  // Read all available bytes in batches to reduce UART call overhead.
   int avail = this->available();
-  if (avail <= 0)
-    return;
-
   uint8_t buf[64];
   while (avail > 0) {
     size_t to_read = std::min(static_cast<size_t>(avail), sizeof(buf));