firmware: raspberrypi: Fix a leak in 'rpi_firmware_get()'

The reference taken by 'of_find_device_by_node()' must be released when
not needed anymore.

Add the corresponding 'put_device()' in the normal and error handling
paths.

Fixes: 4e3d6065 ("ARM: bcm2835: Add the Raspberry Pi firmware driver")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/5e17e5409b934cd08bf6f9279c73be5c1cb11cce.1628232242.git.christophe.jaillet@wanadoo.frSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/firmware/raspberrypi.c

@@ -329,12 +329,18 @@ struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
 
 	fw = platform_get_drvdata(pdev);
 	if (!fw)
-		return NULL;
+		goto err_put_device;
 
 	if (!kref_get_unless_zero(&fw->consumers))
-		return NULL;
+		goto err_put_device;
+
+	put_device(&pdev->dev);
 
 	return fw;
+
+err_put_device:
+	put_device(&pdev->dev);
+	return NULL;
 }
 EXPORT_SYMBOL_GPL(rpi_firmware_get);