feat(plat/imx/imx8m/imx8mp): add in BL2 with FIP

Adds bl2 with FIP to the build required for mbed Linux booting where
we do:

BootROM -> SPL -> BL2 -> OPTEE -> u-boot

If NEED_BL2 is specified then BL2 will be built and BL31 will have its
address range modified upwards to accommodate. BL31 must be loaded from a
FIP in this case.

If NEED_BL2 is not specified then the current BL31 boot flow is unaffected
and u-boot SPL will load and execute BL31 directly.

Signed-off-by: Ying-Chun Liu (PaulLiu) <paulliu@debian.org>
Change-Id: I78914d6002755f733ea866127cb47982a00f9700
3 files changed