Revert "ARM: use generic strnlen_user and strncpy_from_user"

This reverts commit 70aa60950929d8989bb0ebe29dfd465cc6ada672.
Revert "sched/nohz: Rewrite, fix and add more accurate load-avg computation"

This reverts commit ca9d082f0f9a80480f7ef1794d956861e819b123.
Fixed Build error