KVM: x86: simplify is_mmio_spte

We can simply look at bits 52-53 to identify MMIO entries in KVM's page
tables.  Therefore, there is no need to pass a mask to kvm_mmu_set_mmio_spte_mask.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/mmu.h

@@ -51,7 +51,7 @@ static inline u64 rsvd_bits(int s, int e)
 	return ((1ULL << (e - s + 1)) - 1) << s;
 }
 
-void kvm_mmu_set_mmio_spte_mask(u64 mmio_mask, u64 mmio_value, u64 access_mask);
+void kvm_mmu_set_mmio_spte_mask(u64 mmio_value, u64 access_mask);
 
 void
 reset_shadow_zero_bits_mask(struct kvm_vcpu *vcpu, struct kvm_mmu *context);