imx8: Jump from alias to OCRAM address at SPL init

imx8: Jump from alias to OCRAM address at SPL init

When running SPL on iMX8, the A core starts at address 0
which is a alias to OCRAM 0x100000.
The alias only map first 96KB of OCRAM, so this require the
SPL size can't beyond 96KB. But when using SPL DM, the size increase
significantly and may exceed 96KB.
So to fix the problem, we will change SPL linker address to OCRAM
address 0x100000. And then jump to the absolute address not the PC relative
address for entering OCRAM.

Signed-off-by: Ye Li <ye.li@nxp.com>
Reviewed-by: Oleksandr Suvorov <oleksandr.suvorov@toradex.com>