Removing useless headers.

Author: nicolasnoble

os/src/sbrk.c

@@ -1,14 +1,5 @@
-#include <reent.h>
-#include <errno.h>
 #include <stdlib.h>
 
-#include <FreeRTOS.h>
-#include <task.h>
-#include <semphr.h>
-#include <mpu_wrappers.h>
-
-#include "osdebug.h"
-
 extern uintptr_t __heap_start;
 extern uintptr_t __stack_start;