tty/hvc: Use opal irqchip interface if available

Update the hvc driver to use the OPAL irqchip if made available by the
running firmware. If it is not present, the driver falls back to the
existing OPAL event number.
Signed-off-by: NSamuel Mendoza-Jonas <sam@mendozajonas.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

drivers/tty/hvc/hvc_opal.c

@@ -214,7 +214,13 @@ static int hvc_opal_probe(struct platform_device *dev)
 		dev->dev.of_node->full_name,
 		boot ? " (boot console)" : "");
 
-	irq = opal_event_request(ilog2(OPAL_EVENT_CONSOLE_INPUT));
+	irq = irq_of_parse_and_map(dev->dev.of_node, 0);
+	if (!irq) {
+		pr_info("hvc%d: No interrupts property, using OPAL event\n",
+				termno);
+		irq = opal_event_request(ilog2(OPAL_EVENT_CONSOLE_INPUT));
+	}
+
 	if (!irq) {
 		pr_err("hvc_opal: Unable to map interrupt for device %s\n",
 			dev->dev.of_node->full_name);