sched/rt: Remove unnecessary push for unfit tasks

In task_woken_rt() and switched_to_rto() we try trigger push-pull if the
task is unfit.

But the logic is found lacking because if the task was the only one
running on the CPU, then rt_rq is not in overloaded state and won't
trigger a push.

The necessity of this logic was under a debate as well, a summary of
the discussion can be found in the following thread:

  https://lore.kernel.org/lkml/20200226160247.iqvdakiqbakk2llz@e107158-lin.cambridge.arm.com/



Remove the logic for now until a better approach is agreed upon.

Signed-off-by: Qais Yousef <qais.yousef@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Fixes: 804d402f ("sched/rt: Make RT capacity-aware")
Link: https://lkml.kernel.org/r/20200302132721.8353-6-qais.yousef@arm.com