Use -mcpu=cortex-a53 for devices with Kryo

Bug: http://b/69481735

While Clang supports -mcpu=kryo, the GNU assembler doesn't.  Use
Cortex-a53 instead, which is close to Kryo.  The current alternative of
using Krait causes problems when also using armv8, which is not
available in Krait.

Test: Build marlin with internal CL 3248394 cherry-picked.
Change-Id: I571739e6ab4f1b37fafb304ecad2865c9394e04f