KVM: MMU: Fix setting the accessed bit on non-speculative sptes

The accessed bit was accidentally turned on in a random flag word, rather
than, the spte itself, which was lucky, since it used the non-EPT compatible
PT_ACCESSED_MASK.

Fix by turning the bit on in the spte and changing it to use the portable
accessed mask.
Signed-off-by: Avi Kivity <avi@qumranet.com>

arch/x86/kvm/mmu.c

@@ -1192,7 +1192,7 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
 	 */
 	spte = shadow_base_present_pte | shadow_dirty_mask;
 	if (!speculative)
-		pte_access |= PT_ACCESSED_MASK;
+		spte |= shadow_accessed_mask;
 	if (!dirty)
 		pte_access &= ~ACC_WRITE_MASK;
 	if (pte_access & ACC_EXEC_MASK)