stm32mp1: Add support for raw NAND boot device

STM32MP1 platform is able to boot from raw NAND devices.
These modifications add this support using the new
raw NAND framework.

Change-Id: I9e9c2b03930f98a5ac23f2b6b41945bef43e5043
Signed-off-by: Lionel Debieve <lionel.debieve@st.com>
7 files changed