std: One more cpuid fix
std: One more cpuid fix

Don't read from stale eax value, rework the logic a bit so that's clear
what's going on.

raulgrell/zig,andrewrk/zig,zig-lang/zig,raulgrell/zig,raulgrell/zig,andrewrk/zig,zig-lang/zig,raulgrell/zig,raulgrell/zig,zig-lang/zig