i386/tdx: Call KVM_TDX_INIT_VCPU to initialize TDX vcpu

i386/tdx: Call KVM_TDX_INIT_VCPU to initialize TDX vcpu

TDX vcpu needs to be initialized by SEAMCALL(TDH.VP.INIT) and KVM
provides vcpu level IOCTL KVM_TDX_INIT_VCPU for it.

KVM_TDX_INIT_VCPU needs the address of the HOB as input. Invoke it for
each vcpu after HOB list is created.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Link: https://lore.kernel.org/r/20250508150002.689633-26-xiaoyao.li@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>