x86: Set Prefer_No_VZEROUPPER if AVX512ER is available

AVX512ER won't be implemented in any Xeon processors and will be in
all Xeon Phi processors.  Don't check CPU model number when setting
Prefer_No_VZEROUPPER for Xeon Phi.  Instead, set Prefer_No_VZEROUPPER
if AVX512ER is available.  It works with current and future Xeon Phi
and non-Xeon Phi processors.

	* sysdeps/x86/cpu-features.c (init_cpu_features): Set
	Prefer_No_VZEROUPPER if AVX512ER is available.
	* sysdeps/x86/cpu-features.h
	(bit_cpu_AVX512PF): New.
	(bit_cpu_AVX512ER): Likewise.
	(bit_cpu_AVX512CD): Likewise.
	(bit_cpu_AVX512BW): Likewise.
	(bit_cpu_AVX512VL): Likewise.
	(index_cpu_AVX512PF): Likewise.
	(index_cpu_AVX512ER): Likewise.
	(index_cpu_AVX512CD): Likewise.
	(index_cpu_AVX512BW): Likewise.
	(index_cpu_AVX512VL): Likewise.
	(reg_AVX512PF): Likewise.
	(reg_AVX512ER): Likewise.
	(reg_AVX512CD): Likewise.
	(reg_AVX512BW): Likewise.
	(reg_AVX512VL): Likewise.

(cherry picked from commit 1c53cb49)