libaom build failed on arm github actions

[crazywhalecc]

https://github.com/static-php/hosted/actions/runs/30327328481/job/90175323875#step:12:40596

1. Modify zig-cc.sh: convert -march=armv8-a+crc to -mcpu=generic+crc
2. When using zig + aarch64, append -DAOM_ARM_CRC32_FLAG=-mcpu=generic+crc in libaom.php
3. When using zig + aarch64, add -DENABLE_ARM_CRC32=OFF.

[henderkes]

This is resolved in v3-pgo branch, but it requires the extra tooling of llvm tools.

Easier way for now would be to -DAOM_ARM_CRC32_FLAG=-mcpu=generic+crc for now.