[Coco] VCC and NitrOS-9 clock2 module

[Robert Gault]

The documentation that comes with VCC indicates that it emulates the 
DS1315 used in the Cloud-9 hardware. However, when I look at the code 
I'm using with VCC, it is the same as what I use with MESS. That code 
does not match the clock2_cloud9 module but uses the same I/O as the 
clock2_disto4 module.

I have not tested the disto4 module but at least it reads the clock at 
$FF50. My MESS version of swread also reads at $FF50 and it works with VCC.