Find P10 OCCs by looking in /dev

Find the exact OCCs present in the system by looking for the OCC devices
in /dev.  They look like /dev/occ1, /dev/occ2, etc.  The /dev/occ1 entry
will translate to Status object /org/open_power/control/occ0.

In order to handle the case where the application starts before all
devices show up, keep checking until at least 10 seconds have gone by
without a new device showing up (with at least one device present).

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: I42289d55a6266d710b313af0a49070eeacccd725
2 files changed