WIP: clang supports cortex-a15 now

Change-Id: I9872db2237c513f135df32c5147e47edf6eba49f
build: clang: use swift and VFP4 flags for krait

Change-Id: I4c22d6d7d8d2dcf5de26ba3061bba58c74eaf93c
Signed-off-by: Chet Kener <Cl3Kener@gmail.com>