testcase/filesystem: change a way of variable definition
testcase/filesystem: change a way of variable definition

Change a way of buf variable definition to array
in tc_driver_mtd_config_ops() to fix crash issue.

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