ANDROID: sched/fair: Reduce balance interval to 1 jiffy if we have a misfit task

It is quite a common occurrence that we have a misfit task (a task
running on a CPU which is close to the capacity limit of that CPU)
in the system AND we have recently done a load balance operation.
Normal load-balance rate limiting means we can leave those tasks on
the restrictive CPU for a few hundred ms before we move them.

Inspired by the work Leo Yan did on balancing misfits.

This patch reduces the balance interval to one jiffy when there are such
tasks running.

There appears to be no impact on interactive performance from this
patch.

Change-Id: I71d74734d3bd6bca80476c0f466ba48914b7ac02
Signed-off-by: Chris Redpath <chris.redpath@arm.com>
Git-commit: 84c88fc37932db51b87af8df3cedc621cb5c6e97
Git-repo: https://android.googlesource.com/kernel/common


[clingutla@codeaurora.org: Took only partial part from commit
  '84c88fc37932("ANDROID: Combined EAS Load Balance Tweaks")',
  and skip using 1 jiffy for busy balancing]
Signed-off-by: Lingutla Chandrasekhar <clingutla@codeaurora.org>