SMMU: basic driver for init and probing

Introducing the driver in kernel for detecting SMMU features
and initialise the hardware.

Signed-off-by: Oliver Scott <Oliver.Scott@data61.csiro.au>

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.

style: set code width to 120

style: consistently attach return type

Add attach-return-type to astyle

style: consistently align pointer with name

Run astyle with align-pointer=name

SELFOUR-559: Cleanup ARMPageUnmap for IO mappings

This commit moves setThreadState outside the 'perform' stage of the
invocation, and renames decodeARMIOUnmapInvocation to
performPageInvocationUnmapIO as it is actually doing a perform
and not a decode

SELFOUR-558: Consistently name Unmap instead of UnMap

arm-hyp: Remove unneccessary cast

This cast causes problems for the C parser

arm-hyp/tk1: address review comment

arm-hyp/tk1: add guards so other plats can compile.

arm-hyp/tk1: fix bugs found during testing

arm/tk1: a checkpoint for SMMU implementation