[kernel] Add __attribute__(...) for rt_kprintf() to let the compiler check the...

[kernel] Add __attribute__(...) for rt_kprintf() to let the compiler check the format string parameters

Tested in the following environment：
1. Keil uVersion：Arm Compiler v5.06、v6.7、v6.16  
2. Atollic TrueSTUDIO for STM32：GNU v6.3.1  
3. Code Composer Studio：TI Compiler v20.2.2.LTS、GNU v7.2.1

include/rtthread.h

@@ -570,7 +570,12 @@ void rt_components_board_init(void);
 #define rt_kprintf(...)
 #define rt_kputs(str)
 #else
+#if defined(__ARMCC_VERSION) || defined(__GNUC__) || \
+    defined(__TI_COMPILER_VERSION__)
+int rt_kprintf(const char *fmt, ...) __attribute__((format(printf, 1, 2)));
+#else
 int rt_kprintf(const char *fmt, ...);
+#endif
 void rt_kputs(const char *str);
 #endif