Fix lock contention between DMS and ATMS

This causes jank often, and we don't need to call into ATMS
synchronously to update the dream state, as we're not doing that
when starting the dream.

Test: Presubmit, check if AOD still works
Bug: 219502599
Change-Id: Ib3048447e6bb36d78aac39a3dffd3bacf33c5e13