libFLAC: CPUID detecion improvements.

According to docs, it's incorrect to just call CPUID with EAX=1.
One must to ensure that this value is supported.

CPUs that don't support CPUID level 1 are very old, but...
if FLAC tests CPUID presence it should also test CPUID level support.

Also the function FLAC__cpu_have_cpuid_asm_ia32 was simplified
according to the docs at Intel website and in Wikipedia.

Patch-from: lvqcl <lvqcl.mail@gmail.com>
2 files changed