feat(imx8m): add support for high assurance boot

Introduce support for High Assurance Boot (HABv4), which is used to
establish and extend the Root-of-Trust during FW loading at any given
boot stage.

This commit introduces support for HAB ROM Vector Table (RVT) API, which
is normally used by post-ROM code to authenticate additional boot images
(Kernel, FDT, FIT, etc.) that are taking part in the Root-of-Trust.

Signed-off-by: Andrey Zhizhikin <andrey.zhizhikin@leica-geosystems.com>
Change-Id: I780d308369824fa4850844eb9e91768e417166a0