PDP11/VAX: Improve device conflict reporting

Report both devices when address conflict is detected.
PDP11/VAX: Improve device conflict reporting

Ignore disabled devices when searching for conflict.
Blame CPU by default.
PDP11/VAX: Detect vector conflicts, show iospace++

Detect conflicting vector assignments.

Correct show iospace display of high vector for multi-unit devices

Display vectors in DEV_RDX in show iospace
Merge branch 'master' into KDP