Makefile: Remove gcc-wrapper and add some build flags

Signed-off-by: Stratos Karafotis <stratosk@semaphore.gr>
Signed-off-by: poondog <markj338@gmail.com>
ARM: MAKEFILE: remove a15 from makefile to make compiler happy
due to changes in Makefile
Testing has shown this combination for MAKEFILE and ARCH/ARM/MAKEFILE to be the smooth, good on battery and good benchmarks on average

Some flags produced higher benchmarks but made the device stutter slightly. -O3 and -Ofast flags did not prove better in testing, despite larger Images and the additional flags used. In fact, they sometimes caused stutters. Testing stage 1 complete, now lets try some memory optimizations :)

That is all.

Signed-off-by: poondog <markj338@gmail.com>