KVM: Use page_private()/set_page_private() apis

Besides using an established api, this allows using kvm in older kernels.

Signed-off-by: Markus Rechberger <markus.rechberger@amd.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

drivers/kvm/kvm_main.c

@@ -670,7 +670,7 @@ raced:
 						     | __GFP_ZERO);
 			if (!new.phys_mem[i])
 				goto out_free;
- 			new.phys_mem[i]->private = 0;
+			set_page_private(new.phys_mem[i],0);
 		}
 	}