stm32mp1: add authentication support for stm32image

This commit adds authentication binary support for STM32MP1.
It prints the bootrom authentication result if signed
image is used and authenticates the next loaded STM32 images.
It also enables the dynamic translation table support
(PLAT_XLAT_TABLES_DYNAMIC) to use bootrom services.

Signed-off-by: Lionel Debieve <lionel.debieve@st.com>
Change-Id: Iba706519e0dc6b6fae1f3dd498383351f0f75f51