ArmPkg/ArmGicDxe: Expose HardwareInterrupt2 protocol

ArmPkg/ArmGicDxe: Expose HardwareInterrupt2 protocol

The existing HardwareInterrupt protocol lacked a means to configure the
level/edge properties of an interrupt.  The new HardwareInterrupt2
protocol introduced this capability.
This patch updates the GIC drivers to provide the new interfaces.
The changes comprise:
  Update to use HardwareInterrupt2 protocol
  Additions to register info in ArmGicLib.h
  Added new functionality (GetTriggerType and SetTriggerType)

The requirement for this change derives from a problem detected on ARM
Juno boards, but the change is of generic (ARM) relevance.

This commit is in response to review on the mailing list and, as
suggested there, rolls Girish's updates onto Ard's original example.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Girish Pathak <girish.pathak@arm.com>
Signed-off-by: Evan Lloyd <evan.lloyd@arm.com>
Tested-by: Girish Pathak <girish.pathak@arm.com>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>