hw/irq: Declare QOM macros using OBJECT_DECLARE_SIMPLE_TYPE()

hw/irq: Declare QOM macros using OBJECT_DECLARE_SIMPLE_TYPE()

QOM *DECLARE* macros expect a typedef as first argument,
not a structure. Replace 'struct IRQState' by 'IRQState'
to avoid when modifying the macros:

  ../hw/core/irq.c:29:1: error: declaration of anonymous struct must be a definition
  DECLARE_INSTANCE_CHECKER(struct IRQState, IRQ,
  ^

Use OBJECT_DECLARE_SIMPLE_TYPE instead of DECLARE_INSTANCE_CHECKER.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20230113200138.52869-3-philmd@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>