Fix and improve Rx Scheduler mode

Fix and improve Rx Scheduler mode

Fix support of atomic mode and add two new modes: parallel and ordered.
Three modes of synchronization between threads are supported now:
 - parallel - no synchronization between events
 - ordered - relative sequence of events is restored in output queues
 - atomic - only a single thread may process events from a single queue

Change-Id: I9399aa601f0927042ac0f7f1e5f265f4d47724b8
Signed-off-by: Michal Mazur <[email protected]>