Except hw/core/irq.c which implements the forward-declared opaque
qemu_irq structure, hw/adc/zynq-xadc.{c,h} are the only files not
using the typedef. Fix this single exception.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Bernhard Beschow <shentey@gmail.com>
Message-id: 20220509202035.50335-1-philippe.mathieu.daude@gmail.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>