Use the correct logic for CPUID faulting check skipping

We're supposed to run this check only on x86_64/i386, but the current logic
is running the check on all architectures _except_ x86_64/i386. Oops.

```
(gdb) disassemble cpuid_faulting_works
Dump of assembler code for function _ZN2rr20cpuid_faulting_worksEv:
   0x00000000005d3a60 <+0>:     xor    %eax,%eax
   0x00000000005d3a62 <+2>:     ret
End of assembler dump.
```

src/util.cc

@@ -1052,7 +1052,7 @@ bool cpuid_faulting_works() {
  static bool did_check_cpuid_faulting = false;
  static bool cpuid_faulting_ok = false;
 
-#if defined(__i386__) || defined(__x86_64__)
+#if !(defined(__i386__) || defined(__x86_64__))
  did_check_cpuid_faulting = true;
 #endif
  if (did_check_cpuid_faulting) {