That clock pin has in principle nothing too do with your shiftin instruction. This is a setting for the control register to make that pin an i/o pin and not oscilator related.
You use now the internal rc oscillator. When you read well the shiftin instruction than you will see that you say there what pin is the clockpin and what pin in the data pin of you shift thing.
par 5.75 SHIFTIN
SHIFTIN Datapin,Clockpin,Mode,[var{\bits}....]
etc.etc.etc.