refactor: 完成R8裸机lwIP移植并更新文档

Middlewares/Third_Party/SEGGER_RTT/SEGGER_RTT_printf.c

@@ -0,0 +1,30 @@
+#include "SEGGER_RTT.h"
+
+#include <stdarg.h>
+#include <stdio.h>
+
+int SEGGER_RTT_vprintf(unsigned BufferIndex, const char *sFormat, va_list *pParamList)
+{
+    char buffer[SEGGER_RTT_PRINTF_BUFFER_SIZE];
+    int len = vsnprintf(buffer, sizeof(buffer), sFormat, *pParamList);
+
+    if (len < 0) {
+        return len;
+    }
+    if ((unsigned)len > sizeof(buffer)) {
+        len = (int)sizeof(buffer);
+    }
+
+    return (int)SEGGER_RTT_Write(BufferIndex, buffer, (unsigned)len);
+}
+
+int SEGGER_RTT_printf(unsigned BufferIndex, const char *sFormat, ...)
+{
+    int result;
+    va_list args;
+
+    va_start(args, sFormat);
+    result = SEGGER_RTT_vprintf(BufferIndex, sFormat, &args);
+    va_end(args);
+    return result;
+}