Current `CONFIG_PAGING` refers to an experimental implementation
to enable embedded MCUs with some limited RAM space to execute
large programs from some non-random access media.
On-demand paging should be implemented for the kernel mode with
address environment implementation enabled.
Basic work required for uniprocessor CortexR52 (ARMv8R AARCH32) using
GICv3 and CP15 mapped arch timer.
Tested on ARM FVP 11.20.
Port is based on ARMv8R AARCH64 and ARMv7R code. Excuse possible copy-paste leftovers.