arm64: add support for reserved memory defined by device tree

Enable reserved memory initialization from device tree.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Grant Likely <grant.likely@linaro.org>
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Git-commit: 9bf14b7c540ae9ca7747af3a0c0d8470ef77b6ce
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>