KVM: x86: Advertise AVX10_VNNI_INT CPUID to userspace

KVM: x86: Advertise AVX10_VNNI_INT CPUID to userspace

Define and advertise AVX10_VNNI_INT CPUID to userspace when it's supported
by the host.

AVX10_VNNI_INT (0x24.0x1.ECX[bit 2]) is a discrete feature bit
introduced on Intel Diamond Rapids, which enumerates the support for
EVEX VPDP* instructions for INT8/INT16 [*].

Since this feature has no actual kernel usages, define it as a KVM-only
feature in reverse_cpuid.h.

Advertise new CPUID subleaf 0x24.0x1 with AVX10_VNNI_INT bit to
userspace for guest use. It's safe since no additional enabling work
is needed in the host kernel.

[*]: Intel Advanced Vector Extensions 10.2 Architecture Specification
     (rev 5.0).

Tested-by: Xudong Hao <xudong.hao@intel.com>
Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Link: https://patch.msgid.link/20251120050720.931449-5-zhao1.liu@intel.com
Signed-off-by: Sean Christopherson <seanjc@google.com>