Arm32 dynamic function dispatch

Previous change was reverted in 9690b121.
This change added .arch directive to kryo/ to avoid invalid instruction error.

Test: Run bionic unit test.
Test: Use gdb to make sure the right function is selected.
Test: Build previously failed target: make PRODUCT-sdk_phone_arm64-sdk
Change-Id: I14de41851121fc1a0b38c98fda5eb844b6a9695c