fs/smartfs : Fix last sector chain to wrong sector when modify contents
fs/smartfs : Fix last sector chain to wrong sector when modify contents

If user modify current contents to the end of contents, it will update
wrong value for last sector's nextsector

pillip8282/TizenRT,Samsung/TizenRT,sunghan-chang/TizenRT,sunghan-chang/TizenRT,jsdosa/TizenRT,jeongarmy/TizenRT,jeongarmy/TizenRT,Samsung/TizenRT,junmin-kim/TizenRT,sunghan-chang/TizenRT,jsdosa/TizenRT,pillip8282/TizenRT,pillip8282/TizenRT,sunghan-chang/TizenRT,an4967/TizenRT,an4967/TizenRT,jeongchanKim/TizenRT,pillip8282/TizenRT,an4967/TizenRT,jeongchanKim/TizenRT,sunghan-chang/TizenRT,pillip8282/TizenRT,jeongchanKim/TizenRT,junmin-kim/TizenRT,an4967/TizenRT,jeongarmy/TizenRT,sunghan-chang/TizenRT,sunghan-chang/TizenRT,junmin-kim/TizenRT,jeongchanKim/TizenRT,an4967/TizenRT,jsdosa/TizenRT,Samsung/TizenRT,jeongarmy/TizenRT,jeongarmy/TizenRT,jeongchanKim/TizenRT,Samsung/TizenRT,Samsung/TizenRT,pillip8282/TizenRT,junmin-kim/TizenRT,pillip8282/TizenRT,jeongchanKim/TizenRT,jsdosa/TizenRT,jeongarmy/TizenRT,Samsung/TizenRT,an4967/TizenRT,jeongarmy/TizenRT,junmin-kim/TizenRT,junmin-kim/TizenRT,junmin-kim/TizenRT,jsdosa/TizenRT,jeongchanKim/TizenRT,jsdosa/TizenRT,Samsung/TizenRT,jsdosa/TizenRT,an4967/TizenRT