Make ISmartspaceManager non-blocking

Methods from this manager are being called from the SystemUI main
thread, and hitting system_server locks.
All methods return void, and are already using a callback mechanism,
we can make this oneway.

Fixes: 220718061
Test: Deployed on Phone,CTS tests
Change-Id: Ief549fce0d2463547cade4028696cf9431ce3a84