Add missed AVX512VL (128 and 256 bit vector length) extension

identification bit.

Sponsored by:	The FreeBSD Foundation
MFC after:	3 days

sys/x86/include/specialreg.h

@@ -409,6 +409,7 @@
 #define	CPUID_STDEXT_AVX512CD	0x10000000
 #define	CPUID_STDEXT_SHA	0x20000000
 #define	CPUID_STDEXT_AVX512BW	0x40000000
+#define	CPUID_STDEXT_AVX512VL	0x80000000
 
 /*
  * CPUID instruction 7 Structured Extended Features, leaf 0 ecx info

sys/x86/x86/identcpu.c

@@ -963,6 +963,7 @@ printcpuinfo(void)
 				       "\035AVX512CD"
 				       "\036SHA"
 				       "\037AVX512BW"
+				       "\040AVX512VL"
 				       );
 			}