Build kernel with O3

Change-Id: I1e64cf9f5cf1fccd1186d3b15d078cf5a9756061
Optimize flags in arm/arm

Change-Id: I24391eafb3bae3433fcc4a4230fbbf846b13d7fb
Fix unwind

Change-Id: I421d3bba354f81d680a13053c8ec332dda01d78d
graphite

Change-Id: Ia2d5525021f67ee2eba73bd4e67e39e6e0feb2b4
More flags for optimising

Change-Id: Icbfbd519b04376bce15f57638ec5f3dae7a5d98e
add unwind flag to amami defconfig, and ignore a compilation warning

Signed-off-by: Obeida Shamoun <oshmoun100@googlemail.com>