arm: mach-k3: am62: move scratch board area to HSM RAM

On high security devices, ROM enables firewalls to protect the OCSRAM
region access during bootup. Only after TIFS has started (and had
time to disable the OCSRAM firewall region) will we have write access to
the region.

So, move scratch board area to HSM RAM.

Signed-off-by: Kamlesh Gurudasani <kamlesh@ti.com>