i2c: core: Dispose OF IRQ mapping at client removal time

commit e4df3a0b upstream.

Clients instantiated from OF get an IRQ mapping created at device
registration time. Dispose the mapping when the client is removed.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

drivers/i2c/i2c-core.c

@@ -297,6 +297,9 @@ static int i2c_device_remove(struct device *dev)
 		status = driver->remove(client);
 	}
 
+	if (dev->of_node)
+		irq_dispose_mapping(client->irq);
+
 	acpi_dev_pm_detach(&client->dev, true);
 	return status;
 }