MIPS: Loongson-3: Fix BRIDGE irq delivery problem

After commit e509bd7da149dc349160 ("genirq: Allow migration of chained
interrupts by installing default action") Loongson-3 fails at here:

setup_irq(LOONGSON_HT1_IRQ, &cascade_irqaction);

This is because both chained_action and cascade_irqaction don't have
IRQF_SHARED flag. This will cause Loongson-3 resume fails because HPET
timer interrupt can't be delivered during S3. So we set the irqchip of
the chained irq to loongson_irq_chip which doesn't disable the chained
irq in CP0.Status.

Cc: stable@vger.kernel.org
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/20434/
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Cc: Huacai Chen <chenhuacai@gmail.com>

arch/mips/include/asm/mach-loongson64/irq.h

@@ -10,7 +10,7 @@
 #define MIPS_CPU_IRQ_BASE 56
 
 #define LOONGSON_UART_IRQ   (MIPS_CPU_IRQ_BASE + 2) /* UART */
-#define LOONGSON_HT1_IRQ    (MIPS_CPU_IRQ_BASE + 3) /* HT1 */
+#define LOONGSON_BRIDGE_IRQ (MIPS_CPU_IRQ_BASE + 3) /* CASCADE */
 #define LOONGSON_TIMER_IRQ  (MIPS_CPU_IRQ_BASE + 7) /* CPU Timer */
 
 #define LOONGSON_HT1_CFG_BASE		loongson_sysconf.ht_control_base

arch/mips/loongson64/loongson-3/irq.c

@@ -96,12 +96,6 @@ void mach_irq_dispatch(unsigned int pending)
 	}
 }
 
-static struct irqaction cascade_irqaction = {
-	.handler = no_action,
-	.flags = IRQF_NO_SUSPEND,
-	.name = "cascade",
-};
-
 static inline void mask_loongson_irq(struct irq_data *d) { }
 static inline void unmask_loongson_irq(struct irq_data *d) { }
 
@@ -147,11 +141,10 @@ void __init mach_init_irq(void)
 
 	irq_set_chip_and_handler(LOONGSON_UART_IRQ,
 			&loongson_irq_chip, handle_percpu_irq);
+	irq_set_chip_and_handler(LOONGSON_BRIDGE_IRQ,
+			&loongson_irq_chip, handle_percpu_irq);
 
-	/* setup HT1 irq */
-	setup_irq(LOONGSON_HT1_IRQ, &cascade_irqaction);
-
-	set_c0_status(STATUSF_IP2 | STATUSF_IP6);
+	set_c0_status(STATUSF_IP2 | STATUSF_IP3 | STATUSF_IP6);
 }
 
 #ifdef CONFIG_HOTPLUG_CPU