firmware: google: Release devices before unregistering the bus

[ Upstream commit cae0970 ]

Fix a bug where the kernel module can't be loaded after it has been
unloaded as the devices are still present and conflicting with the
to be created coreboot devices.

Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Link: https://lore.kernel.org/r/20191118101934.22526-2-patrick.rudolph@9elements.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 6594669 ("firmware: coreboot: Register bus in module init")
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/firmware/google/coreboot_table.c

@@ -163,8 +163,15 @@ static int coreboot_table_probe(struct platform_device *pdev)
 	return ret;
 }
 
+static int __cb_dev_unregister(struct device *dev, void *dummy)
+{
+	device_unregister(dev);
+	return 0;
+}
+
 static int coreboot_table_remove(struct platform_device *pdev)
 {
+	bus_for_each_dev(&coreboot_bus_type, NULL, NULL, __cb_dev_unregister);
 	bus_unregister(&coreboot_bus_type);
 	return 0;
 }