Revert "makefile: kernel faults with -fschedule-insns2 in GCC 4.8.2"

This reverts commit 6436ef9a94ce016639fa6ef6b2788328fcc6bd03.
Revert "Fix Linaro toolchain warnings"

This reverts commit d42b8e684f87e751d28684834d51639a313220b9.