Enable Bionic optimizations on Cortex Platforms
Add standard method for enabling mfpu and mcpu code optimization

Conflicts:
	core/combo/arch/arm/armv7-a-neon.mk
build: Relax Cortex CFLAGS

 * Always set march=armv7-a
 * Use mtune instead of mcpu. Bad code is generated on A15 otherwise.

Change-Id: Idf8ced8eb0e9d3d4676ca8ec69bf56aed5533bf4