drm/amdkfd: Add chained_runlist_idle_disable flag to pm4_mes_runlist

New flag to disable an idle runlist optimization that is causing soft
hangs with some diffult-to-reproduce customer workloads. This will
serve as a workaround until the problem can be reproduced and the
root-cause determined.

Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Oak Zeng <Oak.Zeng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>