Add build flags for arch variant on Zuma and Zuma Pro.

Zuma supports ARMv9-A and Zuma Pro supports ARMv9.2-A, but
the compilers are currently configured to treat them as
ARMv8.2-A due to various issues that should be fixed now.

Bug: 364383722
Test: presubmit
Flag: EXEMPT adding flag declaration
Change-Id: I3bebda1149548ef94942d9f1a9222fcbef781e3f