KVM: nVMX: Add consistency check for TPR_THRESHOLD[31:4]!=0 without VID

KVM: nVMX: Add consistency check for TPR_THRESHOLD[31:4]!=0 without VID

Add a missing consistency check on the TPR Threshold.  Per the SDM

  If the "use TPR shadow" VM-execution control is 1 and the "virtual-
  interrupt delivery" VM-execution control is 0, bits 31:4 of the TPR
  threshold VM-execution control field must be 0.

Note, nested_vmx_check_tpr_shadow_controls() bails early if "use TPR
shadow" is 0.

Link: https://lore.kernel.org/r/20250919005955.1366256-6-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>