ArmVirtPkg/ArmVirtGicArchLib: adapt ASSERT()s to 64-bit base addresses

ArmVirtPkg/ArmVirtGicArchLib: adapt ASSERT()s to 64-bit base addresses

Since All the GIC base address variables has been aligned to 64-bit, it
doesn't make sense to continue use MAX_UINT32 in ASSERT() statement, so
this patch uses MAX_UINTN to adapt to this kind of change.

Contributed-under: TianoCore Contribution Agreement 1.0
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: Dennis Chen <dennis.chen@arm.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>