x86: add framebuffer info of MBI2 via boot_info

x86: Provide copy of RSDP in bootinfo

This gives a rootserver a way to find the ACPI tables in cases where there is no BIOS region
to scan for an RSDP.

SELFOUR-865: Pass memory map information to user

x86: Pass VBE information from multiboot through bootinfo

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

SELFOUR-421 Introduce explicit device frames and untypeds

Kernel objects cannot be created from device untypeds, with the
exception of frames, which do not get zeroed and cannot be used
as an IPC buffer. Device untypeds additionally cannot be used
in the construction of ASID pools.

This then changes the API to the rootserver (i.e. bootinfo) to
send device untypeds instead of device frames. On ARM these
device untypeds are the same as the previously exported device
frame regions. On x86 PCI scanning is removed and all physical
memory addresses (that are not important for kernel integrity)
are released to the user.

In order to have bits in the frame and untyped caps on ARM the
number of software ASIDs had to be reduced from 2^18 to 2^17,
and the maximum untyped size reduced from 2^31 to 2^30

x86: Populate the freemem list from the multiboot mem list

If the multiboot memory list exists, then it may contain more
than just the single contiguous memory region listed in 'mem_upper'
Therefore we use it to populate a more complete free memory list,
if it exists

x86: Port some of the IOMMU changes on the experimental branch

This changes the IOMMU from using passthrough devices and instead
directly mapping in the reserved regions that are needed for each
device.

x86: With multi-kernel support removed make the kernel PDs etc global instead of passing them around

x86: Do not conditionally compile IOMMU code, use build/run time checks

Guarding code with #ifdef's makes even cursor testing of 'does this code compile'
difficult due to code being hidden by the pre-processor. Using config_set in
regular C if statements is performant as the compiler can trivially detect
dead code at compile time, and at -O1 and above will not even link in symbols
referenced by dead code in these blocks, so this will not bloat image size

x86: Strip multi kernel support from the x86 kernel. This is not used and is conflicting with planned future features

x86: Move APIC frequency calculation to APIC init, instead of doing it before we initialize paging

Rename uint32_t -> word_t in any relevant places

x86: Make x86 the name of the architecture instead of IA32

IA32 is 32bit version of the x86 architecture. Whilst only IA32
is supported, much of the code is generic x86. Using a generic
x86 architecture will aid in future 64bit support