os/pm: remove unused definitions for pm
os/pm: remove unused definitions for pm

The pm_get_domainmetrics and pm_prune_history functions are called
only when CONFIG_PM_METRICS is enabled. So definitions for them is
not needed when config is disabled.

Change-Id: I7e6e15213ca6bb2bb390a60c4b09d076cad0be9c
Signed-off-by: Junhwan Park <7fee488b6f78fc50b291ffc7d10428788977e877@samsung.com>

JunhwanPark/TizenRT,JunhwanPark/TizenRT,JunhwanPark/TizenRT,JunhwanPark/TizenRT,JunhwanPark/TizenRT,JunhwanPark/TizenRT