hw/intc/arm_gicv3: Implement new GICv4 redistributor registers

hw/intc/arm_gicv3: Implement new GICv4 redistributor registers

Implement the new GICv4 redistributor registers: GICR_VPROPBASER
and GICR_VPENDBASER; for the moment we implement these as simple
reads-as-written stubs, together with the necessary migration
and reset handling.

We don't put ID-register checks on the handling of these registers,
because they are all in the only-in-v4 extra register frames, so
they're not accessible in a GICv3.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220408141550.1271295-24-peter.maydell@linaro.org