i2c: move locking operations to their own struct

This makes it trivial to constify them, so do that.

Signed-off-by: Peter Rosin <peda@axentia.se>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 0579442..0722713 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1768,6 +1768,12 @@
 	return i2c_do_add_adapter(to_i2c_driver(d), data);
 }
 
+static const struct i2c_lock_operations i2c_adapter_lock_ops = {
+	.lock_bus =    i2c_adapter_lock_bus,
+	.trylock_bus = i2c_adapter_trylock_bus,
+	.unlock_bus =  i2c_adapter_unlock_bus,
+};
+
 static int i2c_register_adapter(struct i2c_adapter *adap)
 {
 	int res = -EINVAL;
@@ -1787,11 +1793,8 @@
 		goto out_list;
 	}
 
-	if (!adap->lock_bus) {
-		adap->lock_bus = i2c_adapter_lock_bus;
-		adap->trylock_bus = i2c_adapter_trylock_bus;
-		adap->unlock_bus = i2c_adapter_unlock_bus;
-	}
+	if (!adap->lock_ops)
+		adap->lock_ops = &i2c_adapter_lock_ops;
 
 	rt_mutex_init(&adap->bus_lock);
 	rt_mutex_init(&adap->mux_lock);