ANDROID: sched: Introduce uclamp latency and boost wrapper

Introduce a simple helper to read the latency_sensitive flag from a
task. It is called uclamp_latency_sensitive() to match the API
proposed by Patrick.

While at it, introduce uclamp_boosted() which returns true only when a
task has a non-null min-clamp.

Change-Id: I5fc747da8b58625257a6604a3c88487b657fbe7a
Suggested-by: Patrick Bellasi <patrick.bellasi@arm.com>
Signed-off-by: Quentin Perret <quentin.perret@arm.com>