Fix the nx device node in power9
Fix the nx device node in power9

Microcode presents the list of possible nest units in the
"Unit Availability Matrix" vector of the control block.
Hypervisor need to look at this vector to know enabled units
in the system. And the UAV vector only list "nx" and not "nx0",
hence make the changes here.

open-power/ima-catalog,open-power/ima-catalog