arm: DONT_TRANSLATE isIRQPending for GIC v3

This is a shortcut for dealing with the inline assembly inside to
prevent the modifies analysis from picking up every part of the state.

For any future binary correctness analysis, this will need to be
removed, and instead an appeal made to inline assembly being unable to
modify the heap.

Signed-off-by: Rafal Kolanski <rafal.kolanski@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.

arm,SMP: Refactor irq_t structure for smp

Explicitly create a struct definition for irq_t on SMP Arm
configurations. This makes it a lot harder to mistakenly use the wrong
irq encoding when moving an irq between a cnode index and hardware irq
number / core. A couple areas where this was being handled incorrectly
was fixed as part of the refactor. When performing an ipi for masking
PPI interrupts, the idx encoding is used as it fits into a single word.

Document internal machine/interrupt.h interface

Every platform has to implement a standard set of interrupt interfaces
that the kernel uses to interract with a machine's interrupt controller.
Providing a single header file for each of these functions provides a
single location to document their behavior.

trivial: Remove duplicate function prototypes

arm,gicv3: implement setIRQTarget

This allows SPIs to be routed to different cores.

arm,gicv3: update to use virtual ppi irqs

This commit updates the gic_v3 driver to translate virtual irqs to
hardware irq numbers, which enables PPI support for SMP.

arm,gicv3: consisent sgi/ppi checks

This commit brings the gic_v3 is_sgi and is_ppi checks in line with
gicv2 making the code more consistent.

It also removes unneccessary conditionals in the checks, as is_sgi is
always called before is_ppi so the lower bounds checks are not required.

arm,gicv3: use SPI_START

This removes a redundant constant to use one from the gic_common header.

arm,gic: refactor constants into gic_common.h

Move common definitions from gic_v2.h and gic_v3.h into gic_common.h

gic_v3: Support for aarch32

gic: Move common GIC definitions to shared header

Share definitions between gic_pl390.h and gic_v3.h.

gic_v3: Add setIRQTrigger

This enables invocations to change the trigger mode of an IRQ.

gic_v3: Change EOI mode to drop and deactivation

TODO: Decide what EOI mode we want.

gic_v3: Rename driver from gic_500

This driver should be compatible with GIC v3 implementations