KVM: x86: Do reverse CPUID sanity checks in __feature_leaf()

KVM: x86: Do reverse CPUID sanity checks in __feature_leaf()

Do the compile-time sanity checks on reverse_cpuid in __feature_leaf() so
that higher level APIs don't need to "manually" perform the sanity checks.

No functional change intended.

Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Binbin Wu <binbin.wu@linux.intel.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Link: https://lore.kernel.org/r/20241128013424.4096668-21-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>