[Coco] NitrOS-9 Level II and PIA1 FIRQs

[Chuck Youse]

Hey all,

In order to get one of my boards to generate interrupts from the
cartridge slot, I find that I have to not only enable IRQs from CART*
via the GIME, but I also have to turn off FIRQs generated from CART* via
PIA1.  Is there any particular reason why, on Level II, we leave the
PIA1 FIRQ from CART* enabled by default?  

Looking at some other drivers (6551 ACIA) they seem to have to do the
same thing... so it's not just me. 

Wouldn't it make sense to just have the kernel turn off PIA interrupts
on Level II right from the get-go?  The GIME is a far better arbitrator.

C.