[core/sched/cbs] Add TimeQuantum to HRTimer conversion utilities

The CBS controller will operate on a TimeQuantum base, which could be
run-time configured to map on a certain [ns] resolution, depending on the
maximum values allowed for:
1. burst time
2. tasks per RQ
3. round time

Signed-off-by: Patrick Bellasi <derkling@gmail.com>
[core/sched/cbs] [TQ 1/5] Switch to TQ based variables

All the controller internal status time variables are not managed in
Time Quantum (TQ) units, which allows for a configurable minimum time
quantum, e.g. depending on the target architecture datapath width.

All not "_tq_" marked variables are to be considered with HRTimers [ns]
resolution.

Signed-off-by: Patrick Bellasi <derkling@gmail.com>
[core/sched/cbs] [TQ 2/5] Move burst TQ old update

The cached value of the TQ assigned for a round can be updated from within
the burst tuning method.

Signed-off-by: Patrick Bellasi <derkling@gmail.com>
[core/sched/cbs] [TQ 3/5] Update configuration constants

This patch rework the definition of controller constants by introducing
some more high-level configuration parameters, e.g. maximum number of
SE per RQ, or the Max/Min Weight of each SE.

Signed-off-by: Patrick Bellasi <derkling@gmail.com>
[core/sched/cbs] [TQ 4/5] Switch to 64bit multiplications

All the controller state params which requires high resolution are now
performed using 64bit and proper check for overflows on operations.

Signed-off-by: Patrick Bellasi <derkling@gmail.com>
[core/sched/cbs] [TQ 5/5] Add some more consistency checks

A new set of BUG_ON conditions have been added to verify the consistency
of fixed point operations.

Signed-off-by: Patrick Bellasi <derkling@gmail.com>
[core/sched/cbs] Switch to union based flags

The controller status flags, related to both RQ and SE, are now collected
into a union for space saving.
Moreover, a set of get/set/update macros are provided to improve code
readability.

Signed-off-by: Patrick Bellasi <derkling@gmail.com>
[core/sched/cbs] Move reinit into burst setup

The reinitialization is now down per SE, once they re-enter the RQ.

Signed-off-by: Patrick Bellasi <derkling@gmail.com>