ARM: head.S: axxia: Set the NS bit since memory is non-secure

commit  99ff59cbcf846666528dc332d2c15aebb6120f39 from
https://github.com/axxia/linux-yocto.git axxia-linux/v5.10/standard/axxia-dev/base

Axxia AXM55xx memory is by architecture non-secure, so set NS bit.

Signed-off-by: John Jacques <john.jacques@intel.com>
Signed-off-by: Charlie Paul <charlie.paul@windriver.com>
Signed-off-by: Daniel Dragomir <daniel.dragomir@windriver.com>
Signed-off-by: Quanyang Wang <quanyang.wang@windriver.com>