The last 8MB of physical memory on Artik520 family boards is reserved for
secure firmware. Adjust the total amount of the memory defined in
exynos3250-artik5.dtsi to match the memory available for the Linux kernel.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>