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.

libsel4: fix licenses

- some were incorrectly marked GPL (libsel4 is BSD)
- update NICTA --> DATA61 etc
- fix tags D61 --> DATA61
- update year to 2017

SELFOUR-879: expose index and entry constants

SELFOUR-499: X86, ARM: Add userspace invocations for hardware debugging

This commit implements the body of SELFOUR-499. The API exposes the x86 DR0-7
and ARM coprocessor 14 features to userspace by virtualizing them as context-
switched registers in the TCB. Implemented as TCB invocations. This feature is
only built when CONFIG_HARDWARE_DEBUG_API is selected.

* Add low-level support routines for setting, unsetting, getting, enabling
and disabling breakpoints.
* Add support for single-stepping as well.
^ Single-stepping is not supported on ARMv6 since the hardware
doesn't have support.
^ ARM implements single-stepping as instruction breakpoints
configured to fault on every instruction -- this is achieved through
the "mismatch" mode, which is only supported from ARMv7 onwards.
* Also support explicit software break requests, a la "BKPT" and "INT $3".

* New invocations:
* seL4_TCB_SetBreakpoint().
* seL4_TCB_GetBreakpoint().
* seL4_TCB_UnsetBreakpoint().
* seL4_TCB_ConfigureSingleStepping().
* New constants:
^ Event types:
^ seL4_InstructionBreakpoint.
^ seL4_DataBreakpoint.
^ seL4_SoftwareBreakRequest.
^ Access types:
^ seL4_BreakOnRead.
^ seL4_BreakOnWrite.
^ seL4_BreakOnReadWrite.
^ Exports:
^ seL4_NumHWBreakpoints.
^ seL4_NumExclusiveBreakpoints.
^ seL4_NumExclusiveWatchpoints.
^ seL4_NumDualFunctionMonitors.
^ seL4_FirstBreakpoint.
^ seL4_FirstWatchpoint.
^ seL4_FirstDualFunctionMonitor.

See documentation in the seL4 API manual.

x86: IOAPIC/MSI syscalls

Restructure the x86 interrupt handling to allow for a more flexible
method of using IOAPIC and MSI interrupts. The essence of this change
is to allow for the user to pick, for both IOAPIC and MSIs, which
CPU vector to use. Additionally there is future support, in the API,
for seL4 to eventually protect MSI interrupts with the vt-d interrupt
routing tables.

API behaviour for legacy systems using the PIC is preserved

Part of SELFOUR-281

libsel4: Generate libsel4 definitions from the current ARCH as well as the SEL4_ARCH

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

x86: Do not conditionally compile IRQ controller 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

Surrounding benchmarking definitions with "#if CONFIG_MAX_NUM_TRACE_POINTS > 0".

Added support for using multiple tracepoints at the same time.

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