KVM: VMX: fix SMEP and SMAP without EPT

The comment in code had it mostly right, but we enable paging for
emulated real mode regardless of EPT.

Without EPT (which implies emulated real mode), secondary VCPUs won't
start unless we disable SM[AE]P when the guest doesn't use paging.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>