target/i386: Add support for AVX-NE-CONVERT in CPUID enumeration

target/i386: Add support for AVX-NE-CONVERT in CPUID enumeration

AVX-NE-CONVERT is a new set of instructions which can convert low
precision floating point like BF16/FP16 to high precision floating point
FP32, as well as convert FP32 elements to BF16. This instruction allows
the platform to have improved AI capabilities and better compatibility.

The bit definition:
CPUID.(EAX=7,ECX=1):EDX[bit 5]

Add CPUID definition for AVX-NE-CONVERT.

Signed-off-by: Jiaxi Chen <jiaxi.chen@linux.intel.com>
Signed-off-by: Tao Su <tao1.su@linux.intel.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Message-Id: <20230303065913.1246327-6-tao1.su@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>