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

Bug: 11178216

Change-Id: I9922e4cd5ba27e3857798aae5c84299e26e054ea
build: Store no_separate_recovery flag in misc_info

This may be needed during a signing process.

Change-Id: I0ab6f0e615f64c0529e605c2fa62fabf1b1ec52b