Specify -mcpu=cortex-a15 for krait CPU variants.

Bug: 11178216

Signed-off-by: kecinzer <kecinzer@gmail.com>
Add Linker Optimizations

* Make these optional as well as the Clang optimizations.
* Enable using OPTIMIZE_LINKER := true to BoardConfig of your device.

Signed-off-by: kecinzer <kecinzer@gmail.com>
Use -Ofast instead of -O3

Signed-off-by: kecinzer <kecinzer@gmail.com>