Implement BlPhysicalAddressToVirtual() routine

xtldr/protocol.c

@@ -636,6 +636,7 @@ BlpInstallXtLoaderProtocol()
     BlpLdrProtocol.Memory.MapEfiMemory = BlMapEfiMemory;
     BlpLdrProtocol.Memory.MapPage = BlMapPage;
     BlpLdrProtocol.Memory.MapVirtualMemory = BlMapVirtualMemory;
+    BlpLdrProtocol.Memory.PhysicalAddressToVirtual = BlPhysicalAddressToVirtual;
     BlpLdrProtocol.Memory.SetMemory = RtlSetMemory;
     BlpLdrProtocol.Memory.ZeroMemory = RtlZeroMemory;
     BlpLdrProtocol.Protocol.Close = BlCloseProtocol;