Revert "Revert "cpufreq: interactive: remove get_cpu_idle_time because we're now using the generic version from cpufreq.c. Rework boostpulse to boost directly from the cpufreq target function instead of going through the speedtask thread. Add Thread Migration notifier to boost the target cpu that receives a thread migration to ensure no loss of perceived performance.""

This reverts commit a4760104e61dd70ec7dc17af867247afe6b4b270.

Signed-off-by: Simarpreet Singh <simar@linux.com>