Minimize service name mapper lookups

Retrieve the service names from the cached dataset within the zone for a
path and interface, updating the cache when not found. This is used when
initializing property values and service name owners.

Additional performance enhancements to use `GetSubTree` prior to
processing a set speed event will be included under
openbmc/openbmc#2911. This will keep unnecessary `GetSubTree` lookups
from occurring for paths/interfaces that don't exist to further improve
upon initializing properties fan control is defined to use.

Tested:
    First path updates service name cache for all paths sharing the same
interface
    First missing interface on a path updates service name cache for all
paths sharing that interface
    Verify mapper lookups for X number of paths sharing the same
interface is reduced to (X-(X-1))
    NameOwnerChanged events read/update the same set of service name
cache

Change-Id: Ia235b36ba5ae8cda38342d7521f3d87080c2970a
Signed-off-by: Matthew Barth <msbarth@us.ibm.com>

0 files changed, 0 insertions, 0 deletions