feat: small code optimisations

include/stdlib.h

@@ -21,7 +21,7 @@ int atexit(void (*)(void));
 
 int atoi(const char *);
 
-char *itoa(int value, char *buffer, int base);
+char *itoa(uint32_t value, char *buffer, int base);
 
 char *getenv(const char *);
 

include/sys/param.h

@@ -7,5 +7,6 @@
 
 #define MIN(a, b) (((a)<(b))?(a):(b))
 #define MAX(a, b) (((a)>(b))?(a):(b))
+#define DIV_ROUND_UP(a, b) (((a) + ((b) - 1)) / (b))
 
 #endif //NEW_KERNEL_PARAM_H