board: ibex_ast2700: Add FMC header support

Define and parse the header of the First Mutable Code (FMC)
of AST2700 SoCs at runtime phase.

The FMC header contains the information to load prebuilt binaries
required for device initialization such as DRAM and VGA.

Signed-off-by: Chia-Wei Wang <chiawei_wang@aspeedtech.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
3 files changed