mailbox: mtk-cmdq: Do not request irq until we are ready

If the system comes from kexec() the peripheral might trigger an IRQ
befoe we are ready for it. Triggering a crash due to an access to
invalid memory.
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

drivers/mailbox/mtk-cmdq-mailbox.c

@@ -569,12 +569,6 @@ static int cmdq_probe(struct platform_device *pdev)
 	}
 
 	cmdq->irq_mask = GENMASK(cmdq->pdata->thread_nr - 1, 0);
-	err = devm_request_irq(dev, cmdq->irq, cmdq_irq_handler, IRQF_SHARED,
-			       "mtk_cmdq", cmdq);
-	if (err < 0) {
-		dev_err(dev, "failed to register ISR (%d)\n", err);
-		return err;
-	}
 
 	dev_dbg(dev, "cmdq device: addr:0x%p, va:0x%p, irq:%d\n",
 		dev, cmdq->base, cmdq->irq);
@@ -641,6 +635,13 @@ static int cmdq_probe(struct platform_device *pdev)
 
 	cmdq_init(cmdq);
 
+	err = devm_request_irq(dev, cmdq->irq, cmdq_irq_handler, IRQF_SHARED,
+			       "mtk_cmdq", cmdq);
+	if (err < 0) {
+		dev_err(dev, "failed to register ISR (%d)\n", err);
+		return err;
+	}
+
 	return 0;
 }