KVM: x86: add kvm_arch_vcpu_postcreate callback, move TSC initialization

TSC initialization will soon make use of online_vcpus.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

arch/x86/kvm/vmx.c

@@ -3896,8 +3896,6 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx)
 	vmcs_writel(CR0_GUEST_HOST_MASK, ~0UL);
 	set_cr4_guest_host_mask(vmx);
 
-	kvm_write_tsc(&vmx->vcpu, 0);
-
 	return 0;
 }