sched/fair: Optimize the tick path active migration

When a task is upmigrating via tickpath, the lower capacity CPU
that is running the task will wake up the migration task to
carry the migration to the other higher capacity CPU. The migration
task dequeue the task from lower capacity CPU and enqueue it on
the higher capacity CPU. A rescheduler IPI is sent now to the higher
capacity CPU. If the higher capacity CPU was in deep sleep state, it
results in more waiting time for the task to be upmigrated. This can
be optimized by waking up the higher capacity CPU along with waking
the migration task on the lower capacity CPU. Since we reserve the
higher capacity CPU, the is_reserved() API can be used to prevent
the CPU entering idle again.

Change-Id: I7bda9a905a66a9326c1dc74e50fa94eb58e6b705
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
[clingutla@codeaurora.org: Resolved minor merge conflicts]
Signed-off-by: Lingutla Chandrasekhar <clingutla@codeaurora.org>
Signed-off-by: Alexander Winkowski <dereference23@outlook.com>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>