powerpc: Move VPD related tool under common code

VPD related tools (lsvpd, lscfg, lsmcode) is supported on both
pSeries and PowerNV platform. Hence moving these commands under
common code.

Also added support to grab vpd database (/var/lib/lsvpd).

Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
---
 sos/plugins/powerpc.py |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)