Some host like SD and eMMC may use DMA to transter data to SRAM, set memory to non-secure to make sure the address can be accessed. The security of SRAM in OS suppose to initialized in ATF bl31, and the SPL is before the bl31. Signed-off-by: Kever Yang <kever.yang@rock-chips.com> Acked-by: Simon Glass <sjg@chromium.org>