hw/intc/loongarch_pch: Use generic write callback for iomem32_low region For memory region iomem32_low, generic write callback is used. Signed-off-by: Bibo Mao <maobibo@loongson.cn> Reviewed-by: Song Gao <gaosong@loongson.cn> Message-Id: <20250507023148.1877287-11-maobibo@loongson.cn> Signed-off-by: Song Gao <gaosong@loongson.cn>