x86: libatomic: Do not assume ELF constructors run before IFUNC resolvers

x86: libatomic: Do not assume ELF constructors run before IFUNC resolvers

	PR libgcc/60790
	x86: Do not assume ELF constructors run before IFUNC resolvers.
	* config/x86/host-config.h (libat_feat1_ecx, libat_feat1_edx):
	Remove declarations.
	(__libat_feat1, __libat_feat1_init): Declare.
	(FEAT1_REGISTER): Define.
	(load_feat1): New function.
	(IFUNC_COND_1): Adjust.
	* config/x86/init.c (libat_feat1_ecx, libat_feat1_edx)
	(init_cpuid): Remove definitions.
	(__libat_feat1): New variable.
	(__libat_feat1_init): New function.

From-SVN: r260603