hw/intc/arm_gicv3: Wire up distributor and redistributor MMIO regions

Wire up the MMIO functions exposed by the distributor and the
redistributor into MMIO regions exposed by the GICv3 device.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Shannon Zhao <shannon.zhao@linaro.org>
Tested-by: Shannon Zhao <shannon.zhao@linaro.org>
Message-id: 1465915112-29272-14-git-send-email-peter.maydell@linaro.org
