Check if SSE is available with HAS_CPU_FEATURE

Similar to other CPU feature checks, check if SSE is available with
HAS_CPU_FEATURE.

	* sysdeps/i386/fpu/fclrexcpt.c (__feclearexcept): Use
	HAS_CPU_FEATURE to check for SSE.
	* sysdeps/i386/fpu/fedisblxcpt.c (fedisableexcept): Likewise.
	* sysdeps/i386/fpu/feenablxcpt.c (feenableexcept): Likewise.
	* sysdeps/i386/fpu/fegetenv.c (__fegetenv): Likewise.
	* sysdeps/i386/fpu/fegetmode.c (fegetmode): Likewise.
	* sysdeps/i386/fpu/feholdexcpt.c (__feholdexcept): Likewise.
	* sysdeps/i386/fpu/fesetenv.c (__fesetenv): Likewise.
	* sysdeps/i386/fpu/fesetmode.c (fesetmode): Likewise.
	* sysdeps/i386/fpu/fesetround.c (__fesetround): Likewise.
	* sysdeps/i386/fpu/feupdateenv.c (__feupdateenv): Likewise.
	* sysdeps/i386/fpu/fgetexcptflg.c (__fegetexceptflag): Likewise.
	* sysdeps/i386/fpu/fsetexcptflg.c (__fesetexceptflag): Likewise.
	* sysdeps/i386/fpu/ftestexcept.c (fetestexcept): Likewise.
	* sysdeps/i386/setfpucw.c (__setfpucw): Likewise.
	* sysdeps/x86/cpu-features.h (bit_cpu_SSE): New.
	(index_cpu_SSE): Likewise.
	(reg_SSE): Likewise.