Implement a version of the NOR Flash driver that can execute
in standalone MM context.
This is used to access the secure variable storage, it only
supports EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL.
Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@arm.com>