N4 PS/2 keyboard doens't reset reliably

[Neal Crook]

PS/2 keyboard resets ok on 1sr power-up but after a power-cycle it often does not work
This was never a problem wirth the original PS/2 code on my Grant-derived 6809 system, so I may have introduced a sensitivity in my changes for NASCOM support. I think I'll need to add some pin observability to track this down