KVM: introduce KVM_MEM_SLOTS_NUM macro

Introduce KVM_MEM_SLOTS_NUM macro to instead of
KVM_MEMORY_SLOTS + KVM_PRIVATE_MEM_SLOTS

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 7c654aa..924df0d 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -227,11 +227,14 @@
 
 #endif
 
+#ifndef KVM_MEM_SLOTS_NUM
+#define KVM_MEM_SLOTS_NUM (KVM_MEMORY_SLOTS + KVM_PRIVATE_MEM_SLOTS)
+#endif
+
 struct kvm_memslots {
 	int nmemslots;
 	u64 generation;
-	struct kvm_memory_slot memslots[KVM_MEMORY_SLOTS +
-					KVM_PRIVATE_MEM_SLOTS];
+	struct kvm_memory_slot memslots[KVM_MEM_SLOTS_NUM];
 };
 
 struct kvm {