hw/intc/loongson_ipi: Fix resource leak

hw/intc/loongson_ipi: Fix resource leak

Once initialised, QOM objects can be realized and
unrealized multiple times before being finalized.
Resources allocated in REALIZE must be deallocated
in an equivalent UNREALIZE handler.

Free the CPU array in loongson_ipi_unrealize()
instead of loongson_ipi_finalize().

Cc: qemu-stable@nongnu.org
Fixes: 5e90b8db382 ("hw/loongarch: Set iocsr address space per-board rather than percpu")
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Song Gao <gaosong@loongson.cn>
Message-Id: <20240723111405.14208-3-philmd@linaro.org>