mdns: Updated mDNS to explicitely use esp-eth dependency if needed

* Original commit: espressif/esp-idf@5e19b9c951

components/mdns/mdns.c

@@ -17,6 +17,9 @@
 #include "mdns_networking.h"
 #include "esp_log.h"
 #include "esp_random.h"
+#if CONFIG_ETH_ENABLED
+#include "esp_eth.h"
+#endif
 
 #ifdef MDNS_ENABLE_DEBUG
 void mdns_debug_packet(const uint8_t * data, size_t len);