x86: Remove assembly versions of index_cpu_*/index_arch_*

Since assembly versions of HAS_CPU_FEATURE and HAS_ARCH_FEATURE have
been removed,  assembly versions of index_cpu_* and index_arch_* can
also be removed.

Tested on i686 and x86-64 with and without --disable-multi-arch.

	* sysdeps/x86/cpu-features.h [__ASSEMBLER__]
	(index_cpu_*, index_arch_*): Removed.