Revert "arm: Cortex-A15 optimizations"

This reverts commit 6fe3561312b104dc6c01024ec222602650555ece.
Revert "vfp: Cortex-A15 optimizations"

This reverts commit b96740329085dc95c6c7c2a76f81160050f0d732.
Revert "Cortex a15 optimization"

This reverts commit 85d4b561adc1a1295d005591e71135e7fdc45a99.
Build kernel using sambermod toolchain