Check the return value of __get_cpuid().

This function can fail if CPUID is not supported or the maximum
 supported value of EAX is less than the requested one.
Check the return value and explicitly disable all SIMD if it does
 fail.
This was happening before implicitly because of the initialization
 of info[] to zero, but being explicit about it makes it less likely
 someone will break this behavior because they did not realize what
 was going on.