ArmPkg/ArmGicV3Dxe: configure all interrupts as non-secure Group-1

ArmPkg/ArmGicV3Dxe: configure all interrupts as non-secure Group-1

Reassign all interrupts to non-secure Group-1 if the GIC has its DS
(Disable Security) bit set. In this case, it is safe to assume that we
own the GIC, and that no other firmware has performed any configuration
yet, which means it is up to us to reconfigure the interrupts so they
can be taken by the non-secure firmware.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>