kvm: x86: vmx: move some vmx setting from vmx_init() to hardware_setup()

Instead of vmx_init(), actually it would make reasonable sense to do
anything specific to vmx hardware setting in vmx_x86_ops->hardware_setup().

Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>