cpu: Don't set vcpu_dirty when guest_state_protected

cpu: Don't set vcpu_dirty when guest_state_protected

QEMU calls kvm_arch_put_registers() when vcpu_dirty is true in
kvm_vcpu_exec(). However, for confidential guest, like TDX, putting
registers is disallowed due to guest state is protected.

Only set vcpu_dirty to true with guest state is not protected when
creating the vcpu.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Link: https://lore.kernel.org/r/20250508150002.689633-43-xiaoyao.li@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>