Revert "ck-3.16: an attempt to fix i8k+BFS"

This reverts commit 3a3f10753d696f893cf703cef7352f8be2ca45a1.
Revert "ck-3.16: an attempt to fix BFS+ath9k issue"

This reverts commit 85b98dfc2279d478c6aea72d7fac082fab28f55a.
ck-3.16: revert KVM workaround due to proper cond_resched() fix
ck-3.16: bring back scheduler_ipi()
ck-3.16: use tif_need_resched() in cond_resched()
Merge branch 'ck-3.16' into pf-3.16