feat(imx8mm): optionally take params from BL2

Optionally take params from BL2 to offer more flexibility to BL2 on
where and if a BL32 image is expected. This uses imx_bl31_params_parse()
to check if arg0 can safely be accessed as a pointer and actually
contains a bl_params_t structure. If not, the hardcoded parameter
values are used as before.

Change-Id: I06b3012c67e43ea1e42946d863226bd93ccd4638
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
3 files changed