KVM: VMX: remove duplicated segment cache clear

vmx_set_segment() clears segment cache unconditionally, so we should not
clear it again by calling vmx_segment_cache_clear().

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>