Disable power management for boards mec15xxevb_assy6853 and
mec1501modular_assy6885 on latency_measure test. This prevents
the SoC from sleeping which may skew the results. Also this
prevents stopping mid-test due to SoC being in sleep state,
and there are no external interrupts to wake up the SoC.
Fixes#24136
Signed-off-by: Daniel Leung <daniel.leung@intel.com>