Add getObjectFrom* interfaces back in

Got a bit zealous with the removal of "legacy" interfaces
from system_manager.py in https://gerrit.openbmc-project.xyz/#/c/8874/
and removed some still required by phosphor-host-ipmid code for
some of the legacy sensors.

Only adding the minimum required back in with this commit.

Tested: Flashed image on witherspoon and verified host errors
are no longer reported.

Resolves openbmc/openbmc#2975

Change-Id: I6ba601be6310c57122f5e2f1dc37c6eae5417771
Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
1 file changed