serial_autodetect_ftdi: Debuglog FTDI COM port mappings returned

fpgautils.c

@@ -186,6 +186,7 @@ int serial_autodetect_ftdi(detectone_func_t detectone, const char *needle, const
 		if (FT_OK != ftStatus || lComPortNumber < 0)
 			continue;
 		
+		applog(LOG_ERR, "FT_GetComPortNumber(0x%lx (%ld), %ld)", (unsigned long)ftHandle, (long)i, (long)lComPortNumber);
 		sprintf(devpathnum, "%d", (int)lComPortNumber);
 		
 		if (detectone(devpath))