Revert "Disable -mcpu=cortex-a15 flag for krait"

This reverts commit 1fce5a4a00c9f8c68810a7510b41ea81f316171d.
testing...

Change-Id: Ib9a08840df67e2cbdfbde1f73c39fd1d0244c538
Signed-off-by: cj360 <ayunker551@gmail.com>