[Bug] rt_kprintf 使用 %hhu 格式化 int8_t/uint8_t 时输出错误

[caoddx]

RT-Thread Version

5.2.2

Hardware Type/Architectures

apm32f103vb-miniboard

Develop Toolchain

GCC

Describe the bug

使用的是 rt_vsnprintf_tiny，当 int8_t/uint8_t 变量值在 [0, 0x7f] 区间时输出正确，在 [0x80, 0xff] 区间时输出错误。

下面是测试代码和输出结果：

int8_t  i8 = -1;
uint8_t u8 = 255;
rt_kprintf("i8 = %hhd, u8 = %hhd\n", i8, u8);
rt_kprintf("i8 = %hhu, u8 = %hhu\n", i8, u8);

// output:
// i8 = -1, u8 = -1
// i8 = 4294967295, u8 = 4294967295

Other additional context

No response