Add driver init to mg_mgr_init()

src/drivers/same54.h

@@ -1,5 +1,25 @@
 #pragma once
 
+#if MG_ENABLE_TCPIP && defined(MG_ENABLE_DRIVER_SAME54) && MG_ENABLE_DRIVER_SAME54
+
 struct mg_tcpip_driver_same54_data {
     int mdc_cr;
 };
+
+#ifndef MG_MAC_ADDRESS
+#define MG_MAC_ADDRESS MG_MAC_ADDRESS_RANDOM
+#endif
+
+#ifndef MG_DRIVER_MDC_CR
+#define MG_DRIVER_MDC_CR 5
+#endif
+
+#define MG_TCPIP_DRIVER_DATA                                \
+  static struct mg_tcpip_driver_same54_data driver_data = { \
+      .mdc_cr = MG_DRIVER_MDC_CR,                            \
+  };
+
+#define MG_TCPIP_DRIVER_CODE &mg_tcpip_driver_same54
+#define MG_TCPIP_DRIVER_NAME "same54"
+
+#endif