serial: cpm_uart: Don't request IRQ too early for console port

The following message is seen during boot and the activation of
console port gets delayed until normal serial ports activation.

[    0.001346] irq: no irq domain found for pic@930 !

The console port doesn't need irq, perform irq reservation later,
during cpm_uart probe.

While at it, don't use NO_IRQ but 0 which is the value returned
by irq_of_parse_and_map() in case of error. By chance powerpc's
NO_IRQ has value 0 but on some architectures it is -1.

Fixes: 14d893f ("powerpc/8xx: Convert CPM1 interrupt controller to platform_device")
Cc: stable@vger.kernel.org
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Link: https://lore.kernel.org/r/8bed0f30c2e9ef16ae64fb1243a16d54a48eb8da.1664526717.git.christophe.leroy@csgroup.eu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: chleroy

drivers/tty/serial/cpm_uart/cpm_uart_core.c

@@ -1203,12 +1203,6 @@ static int cpm_uart_init_port(struct device_node *np,
 	pinfo->port.fifosize = pinfo->tx_nrfifos * pinfo->tx_fifosize;
 	spin_lock_init(&pinfo->port.lock);
 
-	pinfo->port.irq = irq_of_parse_and_map(np, 0);
-	if (pinfo->port.irq == NO_IRQ) {
-		ret = -EINVAL;
-		goto out_pram;
-	}
-
 	for (i = 0; i < NUM_GPIOS; i++) {
 		struct gpio_desc *gpiod;
 
@@ -1218,7 +1212,7 @@ static int cpm_uart_init_port(struct device_node *np,
 
 		if (IS_ERR(gpiod)) {
 			ret = PTR_ERR(gpiod);
-			goto out_irq;
+			goto out_pram;
 		}
 
 		if (gpiod) {
@@ -1244,8 +1238,6 @@ static int cpm_uart_init_port(struct device_node *np,
 
 	return cpm_uart_request_port(&pinfo->port);
 
-out_irq:
-	irq_dispose_mapping(pinfo->port.irq);
 out_pram:
 	cpm_uart_unmap_pram(pinfo, pram);
 out_mem:
@@ -1425,11 +1417,17 @@ static int cpm_uart_probe(struct platform_device *ofdev)
 	/* initialize the device pointer for the port */
 	pinfo->port.dev = &ofdev->dev;
 
+	pinfo->port.irq = irq_of_parse_and_map(ofdev->dev.of_node, 0);
+	if (!pinfo->port.irq)
+		return -EINVAL;
+
 	ret = cpm_uart_init_port(ofdev->dev.of_node, pinfo);
-	if (ret)
-		return ret;
+	if (!ret)
+		return uart_add_one_port(&cpm_reg, &pinfo->port);
 
-	return uart_add_one_port(&cpm_reg, &pinfo->port);
+	irq_dispose_mapping(pinfo->port.irq);
+
+	return ret;
 }
 
 static int cpm_uart_remove(struct platform_device *ofdev)