kernel: -O3 Kernel optimization

Change-Id: Ib85d31108ad13675ef7b49a294a563a2de4c7a38
build: JustArchi's ArchiDroid Optimizations V3

Change-Id: Ice91cc40e89c56cd604d34b84c5d914f3b4a65c9
build: Allow flashing older build over newer one
vendor: Fix current path value