i2c: i2c_del_adapter: Don't treat removing a non-registered adapter as error

Currently i2c_del_adapter() returns -EINVAL when it gets an adapter which is not
registered. But none of the users of i2c_del_adapter() depend on this behavior,
so for the sake of being able to sanitize the return type of i2c_del_adapter
argue, that the purpose of i2c_del_adapter() is to remove an I2C adapter from
the system. If the adapter is not registered in the first place this becomes a
no-op. So we can return success without having to do anything.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Reviewed-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/i2c-core.c

@@ -1231,7 +1231,7 @@ int i2c_del_adapter(struct i2c_adapter *adap)
 	if (found != adap) {
 		pr_debug("i2c-core: attempting to delete unregistered "
 			 "adapter [%s]\n", adap->name);
-		return -EINVAL;
+		return 0;
 	}
 
 	/* Tell drivers about this removal */