Add memory backed buffer allocation for L0 ray tracing.

This allocates the buffer on a per-device basis and enables ray
tracing on devices that support it when given a kernel with ray
tracing calls.

Signed-off-by: Jim Snow <jim.m.snow@intel.com>

shared/source/command_container/command_encoder.h

@@ -370,4 +370,10 @@ struct EncodeMiArbCheck {
     static void program(LinearStream &commandStream);
     static size_t getCommandSize();
 };
+
+template <typename GfxFamily>
+struct EncodeEnableRayTracing {
+    static void programEnableRayTracing(LinearStream &commandStream, GraphicsAllocation &backBuffer);
+};
+
 } // namespace NEO