Improvement for cachyos-repo.sh to not depend on gcc for zen arch detection.

[sgmihai]

detect_zen_generation() {
    local family=$(awk '/^cpu family/ {print $NF}' /proc/cpuinfo | head -1)
    local model=$(awk '/^model[[:space:]]*:/ {print $NF}' /proc/cpuinfo | head -1)
    
    case "$family" in
        23) (( model <= 31 )) && echo "zen1" || echo "zen2" ;;
        24) echo "zen1" ;;
        25) (( model <= 95 )) && echo "zen3" || echo "zen4" ;;
        26) echo "zen5" ;;
        *) echo "not_zen" ;;
    esac
}

check_supported_znver45() {
    [[ "$(detect_zen_generation)" =~ ^zen[45] ]] && echo 0 || echo 1
}

This is my proposal. Some slim environments (like LXC containers) do not have gcc installed, so adding cachyos repos won't work with the existnig script, if using zen4/5.

I have used the wikichip reference data and also AI to get relevant information about model numbers. Tested on zen4 and it is correct.