replacing all ifndef with pargma once

All the kernel header files now use pargma once rather than the ifndef,
as the pre-processed C files do not change while header files
are protected with pargma once. This will also solve any naming issues
caused by ifndef.

Convert license tags to SPDX identifiers

This commit also converts our own copyright headers to directly use
SPDX, but leaves all other copyright header intact, only adding the
SPDX ident. As far as possible this commit also merges multiple
Data61 copyright statements/headers into one for consistency.

Create device untypeds at boot for all arches

Currently on x86 device untypeds are generated by passing the entire
address space minus any parts that are reserved by the kernel or that
are "real" memory (e.g. kernel image, physical RAM).

On ARM and RISC-V, device untypeds were generated at compile-time from
a device tree. This patch moves ARM and RISC-V to use the same approach
as x86, and moves the code from x86 into a common location that's
shared between the three architectures.

Co-Authored-By: Anna Lyons <anna@gh.st>

Remove assumption on 32-bit memory offsets

On 64-bit platforms physical address could be >2^32 offset from a virtual address. This
changes offsets to match the word size of the target architecture

ARM/SMP: Prepare for ARM SMP adding stubs

Currently building ARM/SMP is broken. This commit:
1- Makes it possible to build ARM/SMP with stubs. Run-time SMP for ARM
DOES NOT WORK.
2- Can be a reference for future SMP targets to follow in order to
layout/add the minimal required files and functions needed to support SMP.
3- Builds for Sabre only. In order to support other platforms, ipi
interrupt ID should be defined in machine.h

Add missing seL4_Uint16 type in the kernel

This type is provided by libsel4 and should be provided by the kernel in the future event
that shared headers actually use the seL4_Uint16 type

aarch64: Check size of unsigned long

Remove include of basic_types

arm/arch/types.h does not require any definitions from basic_types
(other than those from stdint, which is already directly included)

SELFOUR-519: remove map_kernel_devices duplication

* move devices to static array in hardware.h
* use one higher level function to map them in.

SELFOUR-114: remove bootinfo.h duplication

SELFOUR-114: remove duplication of seL4_MessageInfo_t, adjust naming to avoid cparser mangling

SELFOUR-244: symlink duplicated files from libsel4 into kernel rather than duplicating them, remove sanity target as a result

Rationalize standard types

This commit aims to rationalize how we represent different types
for compatiblity between ARM and x86, as well as between 32 and
64 bit code. The choices being made here is to declare that a
uint32_t has a type of 'int', this allows uint32_t to be declared
consistently across 32 and 64 bit (at least in GCC).
The word_t type is declared using a 'long' (not a uint32_t or uint64_t) to
allow for a word_t to be backed by the same type on both 32 and 64 bit
All other types that want to be declared as the size of a native word
get declared in terms of a word_t

Release snapshot