kernel: heap: rename resereved 'rewind'
kernel: heap: rename resereved 'rewind'

This symbol is reserved and usage of reserved symbols violates the
coding guidelines. (MISRA 21.2)

NAME
   fgetpos, fseek, fsetpos, ftell, rewind - reposition a stream

SYNOPSIS
   #include <stdio.h>

   void rewind(FILE *stream);

Signed-off-by: Anas Nashif <0d9952ec84ac43c159f6b7e7ed99a9080c00dd6e@intel.com>

galak/zephyr,galak/zephyr,galak/zephyr,Vudentz/zephyr,finikorg/zephyr,Vudentz/zephyr,Vudentz/zephyr,finikorg/zephyr,galak/zephyr,finikorg/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,finikorg/zephyr,Vudentz/zephyr,nashif/zephyr,nashif/zephyr,nashif/zephyr,nashif/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr