The IAR0/IAR1 register is used to acknowledge an interrupt - a read of the
register activates the highest priority pending interrupt and provides its
interrupt ID. Activating an interrupt can change the CPU's virtual interrupt
state - this change makes sure the virtual irq state is updated.

Signed-off-by: Jeff Kubascik <jeff.kubascik@dornerworks.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20200113154607.97032-1-jeff.kubascik@dornerworks.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>