i2c: Check for address business before creating clients

We check for address business in i2c_probe_address(),
i2c_detect_address() and i2c_new_probed_device(), but this isn't
sufficient. Drivers can call i2c_attach_client() and
i2c_new_device() on any address, so we must check the address there
as well.

This fixes bug #11239:
http://bugzilla.kernel.org/show_bug.cgi?id=11239

Signed-off-by: Jean Delvare <khali@linux-fr.org>
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index c16dcad..550853f 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -813,7 +813,12 @@
 int i2c_attach_client(struct i2c_client *client)
 {
 	struct i2c_adapter *adapter = client->adapter;
-	int res = 0;
+	int res;
+
+	/* Check for address business */
+	res = i2c_check_addr(adapter, client->addr);
+	if (res)
+		return res;
 
 	client->dev.parent = &client->adapter->dev;
 	client->dev.bus = &i2c_bus_type;