KVM: VMX: Use kvm_read_cr4() to get cr4 value

Directly use vcpu->arch.cr4 is not recommended since it gets stale value
if the cr4 is not available.

Use kvm_read_cr4() instead to ensure correct value.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Link: https://lore.kernel.org/r/20230410125017.1305238-2-xiaoyao.li@intel.com


Signed-off-by: Sean Christopherson <seanjc@google.com>