KVM: use kvm_memslots whenever possible

kvm_memslots provides lockdep checking.  Use it consistently instead of
explicit dereferencing of kvm->memslots.

Reviewed-by: Radim Krcmar <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d42d8ac..8918e23 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7782,6 +7782,7 @@
 				const struct kvm_memory_slot *old,
 				enum kvm_mr_change change)
 {
+	struct kvm_memslots *slots;
 	struct kvm_memory_slot *new;
 	int nr_mmu_pages = 0;
 
@@ -7803,7 +7804,8 @@
 		kvm_mmu_change_mmu_pages(kvm, nr_mmu_pages);
 
 	/* It's OK to get 'new' slot here as it has already been installed */
-	new = id_to_memslot(kvm->memslots, mem->slot);
+	slots = kvm_memslots(kvm);
+	new = id_to_memslot(slots, mem->slot);
 
 	/*
 	 * Dirty logging tracks sptes in 4k granularity, meaning that large