os/arch: remove dependancy between DDR and ARCH_BOARD_CY4390X
os/arch: remove dependancy between DDR and ARCH_BOARD_CY4390X

Any board can use DDR, this is not specific to Cypress board.

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