mmc: dw_mmc: exynos: configure SMU in exynos5420

Exynos5420 Mobile Storage Host controller has Security Management
Unit (SMU) for channel 0 and channel 1 (mainly for eMMC).
This time, SMU configuration is set for non-encryption mode.

Signed-off-by: Yuvaraj Kumar C D <yuvaraj.cd@samsung.com>
Signed-off-by: Alim Akhtar <alim.akhtar@samsung.com>
Tested-by: Jaehoon Chung <jh80.chung@samsung.com>
Acked-by: Seungwon Jeon <tgih.jun@samsung.com>
Signed-off-by: Chris Ball <cjb@laptop.org>