Revert "Warnings : Fix Linaro toolchain warnings"

This reverts commit d44bc99dcad46f543e0ffaecfeb087f5649dea57.
Revert "ARM: 7670/1: fix the memset fix"

This reverts commit 5114e0a2a9bd2976a6efdce20f97326c3445b380.
Revert "ARM: 7668/1: fix memset-related crashes caused by recent GCC (4.7.2) optimization"

This reverts commit 034ed985766e22c60b211832722ab42924b36c31.
lib: update RWSEM to Linux 3.10 (by AndreiLux)
epoll: optimize EPOLL_CTL_DEL using rcu