ARM: stm32: Pass ROM API table pointer to U-Boot proper

The ROM API table pointer is no longer accessible from U-Boot, fix
this by passing the ROM API pointer through. This makes it possible
for U-Boot to call ROM API functions to authenticate payload like
signed fitImages.

Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Signed-off-by: Marek Vasut <marex@denx.de>