irqchip/loongson-eiointc: Fix registration of syscore_ops

irqchip/loongson-eiointc: Fix registration of syscore_ops

When support suspend/resume for loongson-eiointc, the syscore_ops
is registered twice in dual-bridges machines where there are two
eiointc IRQ domains. Repeated registration of an same syscore_ops
broke syscore_ops_list. Also, cpuhp_setup_state_nocalls is only
needed to call for once. So the patch will corret them.

Fixes: a90335c2dfb4 ("irqchip/loongson-eiointc: Add suspend/resume support")
Cc: stable@vger.kernel.org
Signed-off-by: Jianmin Lv <lvjianmin@loongson.cn>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230407083453.6305-4-lvjianmin@loongson.cn