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

Bug: 11178216

Change-Id: I9922e4cd5ba27e3857798aae5c84299e26e054ea

Conflicts:
	core/combo/arch/arm/armv7-a-neon.mk

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

Bug: 11178216

Change-Id: I9922e4cd5ba27e3857798aae5c84299e26e054ea

Conflicts:
	core/combo/arch/arm/armv7-a-neon.mk