armv8: layerscape: properly use CPU_RELEASE_ADDR

armv8: layerscape: properly use CPU_RELEASE_ADDR

The generic armv8 code already has support to bring up the secondary
cores. Thus, don't hardcode the jump in the layerscape lowlevel_init to
the spin table code; instead just return early and let the common armv8
code handle the jump. This way we can actually use the CPU_RELEASE_ADDR
feature.

Signed-off-by: Michael Walle <michael@walle.cc>
[Rebased, Removed kontron_sl28.h change as file does not exist]
Signed-off-by: Priyanka Jain <priyanka.jain@nxp.com>