Hi,

Attached patch adds a debug print when keyboard data register is read, 
and removes a dead define at top of file.

It also diminishes registred memory address range when i8042 is 
memory-mapped. Indeed, i8042 only has 2 ports (data and control), and 
it_shift parameter can be used to widen this range again.
Memory-mapped i8042 is only used in MIPS Pica 61 emulation, which 
doesn't suffer from this change.

Hervé