Fix issue with TOC in man page
Fix issue with TOC in man page

- Whe the geopm_pio.7 roff file is generated the contents
  of the files in the :toc: list are expanded.
- To avoid this, make a list of links rather than using the
  sphinx :toc: abstraction.

Signed-off-by: Christopher M. Cantalupo <9cf3ecca60a3dd7112ab0e7250bedb8a752e3958@intel.com>

geopm/geopm,cmcantalupo/geopm,cmcantalupo/geopm,cmcantalupo/geopm,geopm/geopm,geopm/geopm,geopm/geopm,cmcantalupo/geopm,geopm/geopm,cmcantalupo/geopm