Test PR for generating cubemap mips

note ibl skips prefilter step and prefilter just becomes the cubeRefl.getCubemap()

Generates cubemap mip levels after the bake correctly on DX side.

Engine/source/gfx/gfxCubemap.h

@@ -70,6 +70,7 @@ public:
    /// Returns the size of the faces.
    virtual U32 getSize() const = 0;
 
+   virtual void generateMipMaps() = 0;
    /// Returns the face texture format.
    virtual GFXFormat getFormat() const = 0;